[ J - 5A - B - 2023 ] IN THE SUPREME COURT OF PENNSYLVANIA

EASTERN DISTRICT TODD, C.J., DONOHUE, DOUGHERTY, WECHT, MUNDY, BROBSON, JJ.

DIANE ZILKA, Appellant

v.

TAX REVIEW BOARD CITY OF PHILADELPHIA, Appellee : : : : : : : : : : : : No. 20 EAP 2022 Appeal from the Order of the Commonwealth Court entered on January 7, 2022 , at No. 1063 CD 2019 affirming the Order entered on June 26, 2019 , in the Court of Common Pleas, Philadelphia County, Civil Division at Nos. 02438 and 02439, Oc tober Term 2018. ARGUED: March 7, 2023 DIANE ZILKA, Appellant

v.

TAX REVIEW BOARD CITY OF PHILADELPHIA, Appellee : : : : : : : : : : : : No. 21 EAP 2022 Appeal from the Order of the Commonwealth Court entered on January 7, 2022 , at No. 1064 CD 2019 affirming the Order entered on June 26, 2019 , in the Court of Common Pleas, Philadelphia County, Civil Division at Nos. 02438 and 02439, October Term 2018. ARGUED: March 7, 2023

O PINION

CHIEF JUSTICE TODD DECIDED: NOVEMBER 22, 2023 In this appeal by allowance, we consider whether the City of Philadelphia (the “City” or “Philadelphia” ) unconstitutionally discriminated against interstate commerce by subjecting a Philadelphia resident who worked exclusively out of state to its wage tax (the “Philadelphia Tax”), and allowing her credit against that tax only for the local income tax[ J

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she paid to another jurisdiction, while declining to afford her additional credit f or the out

of

- state income tax she paid. In conjunction with this overarching issue, we must determine whether, for purposes of the dormant Commerce Clause analysis implicated herein , state and local taxes must be considered in the aggregate. For the rea sons that follow, we conclude that state and local taxes need not be aggregated in conducting a dormant Commerce Clause analysis, and that , ultimately, the City’s tax scheme does not discriminate against interstate commerce . Accordingly, we affirm the ord er of the Commonwealth Court. I. Introduction : The Commerce Clause By way of background, the Commerce Clause provides that “Congress shall have Power . . . To regulate Commerce . . . among the several States.” U.S. Const. art. 1, § 8, cl. 3 (first ellip ses original). While the Commerce Clause is an express grant of power to Congress, the United States Supreme Court has consistently held that the language also contains a “negative command, known as the dormant Commerce Clause,” which prohibits “certain s tate taxation even when Congress has failed to legislate on the subject.” Comptroller of Treasury of Md. v. Wynne , 575 U.S. 542, 549 (2015) (quoting Okla. Tax C o mm’n v. Jefferson Lines, Inc. , 514 U.S. 175, 179 (1995)). Notably, t he high Court has explain ed that the crux of the dormant Commerce Clause is that a state “may not tax a transaction or incident more heavily when it crosses state lines than when it occurs entirely within the State,” id. (quoting Armco Inc. v. Hardesty , 467 U.S. 638, 642 (1984)), nor may it “impose a tax which discriminates against interstate commerce either by providing a direct commercial advantage to local business, or by subjecting interstate commerce to the burden of ‘multiple taxation,’” id. at 549

- 50 (quoting Nw. States Port land Cement Co. v. Minnesota , 358 U.S. 450, 458 (1959)). However, where alleged taxation disparities stem from the combined effect of two otherwise lawful income tax schemes,[ J

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the Court has manifestly determined that there is no discrimination against interstate

commerce. See Moorman Mfg. Co. v. Bair , 437 U.S. 267, 279 (1978) (observing that “[t]he prevention of duplicative taxation[] . . . would require national uniform rules for the division of income,” which is a t ask solely in the province of Congress)

. Significantly, i n Complete Auto Transit, Inc. v. Brady , 430 U.S. 274 (1977) , the high Court crafted a four

- part test for determining whether a state or local tax unconstitutionally burdens interstate commerce. Un der this test , a tax does not violate the dormant Commerce Clause if it: (1) is applied to an activity with a substantial nexus to the taxing state; (2) is fairly apportioned; (3) does not discriminate against interstate commerce; and (4) is fairly relate d to the services provided by the state. 1 Id. at 279. Relevant to the instant appeal , to determine whether a tax is fairly apportioned, a court must assess whether the tax is internally and externally consistent. The high Court has explained that
i nter nal consistency is met “when the imposition of a tax identical to the one in question by every other State would add no burden to interstate commerce that intrastate commerce would not also bear.” Jefferson Lines , 514 U.S. at 185. Conversely, an internal ly inconsistent tax demonstrates that a state “is attempting to take more than its fair share of taxes from the interstate transaction, since allowing such a tax in one State would place interstate commerce at the mercy of those remaining States that might impose an identical tax.” Id. (citation omitted). As for external consistency, a court must examine “the economic justification for the State’s claim upon the value taxed, to discover whether a State’s tax reaches beyond that portion of value that is fa irly attributable to economic activity within the taxing State.” Id. (citation omitted).

1 Presently, Appellant contends that the Philadelphia Tax violates the fair apportionment and discrimination prongs of the Complete Auto test.[ J

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R elevant to the instant appeal , in 2015, the high Court grappled with these issues
in Wynne , supra . Therein, the Court examined Maryland’s tax scheme, under which Maryland required its residents to pay a “state” income tax which was set at a graduated
rate , and a “county” income tax, the rate of which varied by county for wages earned both in and out of state, and additionally imposed upon nonresidents a “special no nresident” tax on their income earned in Maryland. Wynne , 575 U.S. at 545

- 46. While Maryland allowed residents who earned income out of state a credit against the state tax, it did not permit them any credit against the county tax. Id. at 546. Critically, the high Court determined that, “[d] espite the names that Maryland ha [d] assigned to these taxes, both [were] State taxes, ” noting that “ both [were] collected by the State ’ s Comptroller of the Treasury. ” Id. (citation omitted). Tur ning to Complete Auto , the Wynne Court observed that the internal consistency test “ allows courts to isolate the effect of a defendant State ’ s tax scheme ” by

“ hypothetically assuming that every State has the same tax structure .” Wynne , 575 U.S. at 562. I n this vein, the Court explained that the internal consistency test permits courts to distinguish between “ tax schemes that inherently discriminate against interstate commerce without regard to the tax policies of other States, ” and “ tax schemes that creat e disparate incentives to engage in interstate commerce (and sometimes result in double taxation) only as a result of the interaction of two different but nondiscriminatory and internally consistent schemes ,” emphasizing that the former category of taxes a re generally unconstitutional, while the latter are not. Id. (citing, inter alia , Armco Inc. , 467 U.S. at 645

- 46; Moorman Mfg. Co. , 437 U.S. at 277 n.12). Ultimately, bearing in mind these principles, the Court found that Maryland’s county
tax was uncon stitutional because Maryland failed to permit residents a credit for similar taxes paid to out

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residents’ income. Indeed, applying the internal consistency test to Maryland’s tax

sc heme, the Court assumed that all states adopted the following taxes, consistent with Maryland’s county and special nonresident taxes: “ (1) a 1.25% tax on income that residents earn in State, (2) a 1.25% tax on income that residents earn in other jurisdict ions, and (3) a 1.25% tax on income that nonresidents earn in State. ” 2 Id. at 564

- 65. The Court observed that, under this scenario, an in

- state resident and an out

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- state resident would incur disparate tax obligations:

Assume

. . . that two taxpayers, April and Bob, both live in State A, but that April earns her income in State A whereas Bob earns his income in State B. In this circumstance, Bob will pay more income tax than April solely because he earns income interstate. Specifi cally, April will have to pay a 1.25% tax only once, to State A. But Bob will have to pay a 1.25% tax twice: once to State A, where he resides, and once to State B, where he earns the income. Id. at 565. Based on this analysis , the Court concluded that Maryland’s tax scheme was unconstitutional, as the disparate treatment of interstate commerce emanating therefrom

was “not simply the result of [the tax scheme’s] interaction with the taxing schemes of other States,” but, rather, stemmed fro m inherent discrimination contained within the scheme

. Id. (citations omitted). Aptly, the Court stressed that “Maryland could remedy the infirmity in its tax scheme by offering, as most States do, a credit against income taxes paid to other States ,” wh ich would vindicate the tax scheme under the internal consistency test. Id. at 568 (citation omitted). Illustrating this point, the Court tweaked the above hypothetical scenario to assume that all states impose those same taxes but also allow a credit ag ainst income taxes paid by residents to other jurisdictions. Under such circumstances, the

2 The Court appears to have used the 1.25% rate for all three taxes simply for ease of applying the internal consi stency test, as the rate is not reflective of the actual rates of Maryland’s relevant taxes.[ J

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Court noted that “ April (who lives and works in State A) and Bob (who lives in State A but works in State B) would pay the same tax ,” observing that “ April would pa y a 1.25% tax only once (to State A), and Bob would pay a 1.25% tax only once (to State B, because State A would give him a credit against the tax he paid to State B). ” Id. However , as Maryland offered no such credit against its county tax, the Court dec lared the tax scheme unconstitutional. II. Factual and Procedural Background With that backdrop, we now turn to the facts of this appeal. In April 2017 and June 2017, Appellant Diane Zilka filed petitions with the City’s Department of Revenue (the “Depar tment”) , seeking refunds for the Philadelphia Tax she paid from 2013 to 2015 , and in 2016, respectively. 3 D uring the relevant tax years, Appellant resided in the City, but worked exclusively in Wilmington, Delaware. Thus, she was subject to four income taxes (and tax rates) during that time: the Philadelphia Tax (3.922%); the Pennsylvania Income Tax (“PIT”) (3.07%); the Wilmington Earned Income Tax (“Wilmington Tax”) (1.25%) ; and the Delaware Income Tax (“DIT”) (5%)

. 4 The Commonwealth granted Appellant credit for her DIT liability to completely offset the PIT she paid for the tax years 2013 through 2016; because of the respective tax rates in our Commonwealth versus the State of Delaware, after this offsetting, Appell ant paid the remaining 1.93% in DIT . Although the City similarly credited against Appellant’s Philadelphia Tax liability the amount she paid in the Wilmington Tax

— specifically, the City credited Appellant 1.25% against her Philadelphia Tax liability of 3.922%, leaving her with a remainder of 2.672% owed to the City

—

3 While Appellant filed two separate refund petitions, for ease of reference, we will simply refer to her request for refunds singularly, as the resolution of each petition hinges upon the same issue.

4 Herein, we will employ the figures utilized by the Commonwealth Court below, which represent the tax rates of the 2014 tax year.[ J

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Appellant claim ed that the City was required to afford her an additional credit of 1.93% against the Philadelphia Tax, representing the remainder of the DIT she owed after the Commonwealth c redited Appellant for her PIT.
A fter the City refused to permit her this credit against her Philadelphia Tax liability,
A ppellant appealed to the City’s Tax Review Board (the “Board”). F ollowing two hearings on the matter, the Board denied Appellant’s ref und request. Appellant then appealed to the trial court, which affirmed the decision of the Board without taking additional evidence

. Thereafter, Appellant appealed to the Commonwealth Court, renewing her claim that she was owed a credit against the Phi ladelphia Tax for the portion of her DIT liability which was not offset/ credited against her PIT . Appellant suggested that the failure to grant her this credit amounted to double taxation in violation of the Commerce Clause. More specifically, Appellant asserted that , because the City failed to offset her Philadelphia Tax with t he remainder of her DIT liability, the tax scheme fail ed the Complete Auto test

. In that regard , Appellant contended that: (1) the tax is not fairly apportioned, as it lacks a me chanism to mitigate the risk of duplicative taxation for income earned from interstate commerce, thus failing to meet the internal and external consistency tests; and (2) the City’s partial credit practice discriminatorily forces her to pay more in taxes t han her intrastate counterparts. Notably, in support of her claim, Appellant relied heavily on Wynne , supra , contending that the high Court’s decision requires state and local taxes to be considered as one

. In a unanimous, unpublished memorandum opinion authored by Judge Michael H. Wojcik, the Commonwealth Court affirmed. Zilka v. Tax Rev. Bd. City of Phila. , 1063

- 1064 C.D. 2019 (Pa. Cmwlth. filed Jan. 7, 2022) ( en banc ). In so doing, t he court concluded th at Appellant was not subject to double taxation in violation of the Commerce Clause , as she never paid more than one local and one state tax at a time. From the[ J

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court’s perspective, the City taxed Appellant at the same rate (3.922%) as it taxed other resi dents who worked in Pennsylvania, and she paid 1.93% more in taxes than her intrastate counterparts only because she chose to work in Delaware, which charges a higher income tax than Pennsylvania. In deed , the court highlighted that the City credited Appel lant the full amount of her Wilmington Tax liability to offset the Philadelphia Tax she incurred , while declining to apply tax credit for the balance of the DIT which remained “unused” after offsetting the PIT (namely, 1.93%). The court emphasized that , i n its view, the City’s decision not to apply the remainder of Appellant’s DIT to offset her Philadelphia Tax simply did not amount to double taxation. Nevertheless, assuming that there was a risk of double taxation, the court analyzed the City’s taxation s cheme under the Complete Auto test. First, focusing on the “fair apportionment” prong of the test, the court determined that the Philadelphia Tax is internally consistent, as “all individuals earning income outside of their home locality would receive a c redit for income taxes paid to the foreign locality and would pay no more than their intrastate counterpart” if the wage tax were imposed in every jurisdiction. Id. at 8. Likewise, the court found that the Philadelphia Tax meets the external consistency test, explaining that the tax “reasonably reflects how and where [Appellant’s] income is generated ,” and “is not taxing all of [Appellant’s] income regardless of source.” Id. at 9. In that vein, the court opined that the City “fairly apportio ns the tax according to its relation to the income by providing a credit for the tax owed to Wilmington,” such that the City never taxed more than its fair share of Appellant’s wages. Id. Relatedly, the court reasoned that “Philadelphia’s provision of mu nicipal benefits and services to its residents provides sufficient economic justification for the imposition of [the Philadelphia Tax ].” Id. (citing Lawrence v. State Tax Comm’n of Miss. , 286 U.S. 276, 279 (1932) (observing that “domicile in itself establ ishes a basis for taxation,” as “[e]njoyment of the privileges of[ J

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residence within the state, and the attendant right to invoke the protection of its laws, are inseparable from the responsibility for sharing the costs of government”)). Next, turning to t he “discrimination” prong of the Complete Auto test, the court highlighted that the City taxes all of its residents’ income at the rate of 3.922% and full y credit s any similar taxes a resident paid to another jurisdiction. To that end, t he court noted tha t, here, because Appellant’s income was taxed at 1.25% by Wilmington, the City applied 1.25% credit toward her Philadelphia Tax

. Thus , the court found that Appellant did not pay double taxes on her income; instead, the court determined , she paid the same 3.922% rate as all of the City’s residents, with the only difference being that the City “r eceiv[ed] only 2.67% , while Wilmington . . . receiv[ed] 1.25%.” Id. at 10. Finally, the court found that “ Wynne does not compel Philadelphia to apply an additional credit for any dissimilar taxes, such as the [ DIT] . . . .” Id. at 13. From the court’s perspective, “[a]lthough the Wynne Court held that Maryland was required to offset its so

called ‘county’ tax agai nst other ‘state’ taxes, the ‘county’ tax was actually a state tax because it was administered, adopted, mandated, and collected by the state.” Id. Conversely, the court emphasized that, here, “both the [ Philadelphia Tax ] and Wilmington Tax are municipal taxes.” Id. On that basis, the court opined that Appellant’s taxes were appropriately credited in an “apples to apples” manner

— with Delaware’s state tax offsetting Pennsylvania’s state tax and Wilmington’s municipal tax offsetting the City’s municipal tax. This approach, in the court’s view, comport ed with the high Court’s holding
in Wynne , and, moreover, passe d constitutional muster. Thus, reiterating that the taxation of Appellant’s income in excess of the taxation of her intrastate cohorts stem med solely from her decision to work in Delaware, which has a higher rate of taxation than Pennsylvania

— and not fro m the City’s tax scheme

— the court found that Appellant was not subject to double taxation. Accordingly, the court affirmed the trial court’s decision.[ J

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Appellant subsequently filed a petition for allowance of appeal with our Court, and we granted review to consider whether the City, in declining to apply the remainder of Appellant’s DIT liability to offset her Philadelphia Tax liability, discriminated against interstate commerce in violation of the dormant Commerce Clause

. 5 As illuminated by the parties ’ arguments, this question necessarily requires us to determine whether state and local taxes are indistinguishable when analyzing a challenged tax scheme under the dormant Commerce Clause. III. Arguments Regarding that prefatory issue , Appellant initiall y contends that state and local income tax burden s must be aggregated in reviewing a dormant Commerce Clause challenge , in essence, maintaining that local or municipal taxes, such as the Philadelphia Tax , are indistinguishable from state taxes because poli tical subdivisions are creatures of the state. According to Appellant, in Associated Industries of Missouri v. Lohman , 511

5 The question, as phrased by Appellant, reads:

[Appellant] , a Philadelphia resident wh o worked in Wilmington, Delaware, was subject to [the PIT, the Philadelphia Tax, the DIT, and the Wilmington Tax]

. Pennsylvania allowed [ Appellant ] to credit [the] DIT paid against her PIT liability. The City

. . . allowed [Appellant] to credit [the] Wil mington Tax paid against her [Philadelphia Tax] liability. [The] DIT [which Appellant] paid exceeded the PIT credit she was allowed (“Unapplied Credit”). The City did not allow [Appellant] to apply the Unapplied Credit against the [Philadelphia] Tax. Th e U.S. Supreme Court held the Commerce Clause of the U.S. Constitution dictates that taxing jurisdictions must grant their residents a credit for state and local income taxes paid to other state and local taxing jurisdictions. [ Wynne , supra ]

. Did the Com monwealth Court err, as a matter of law, where it held it was constitutional for the City not to apply [Appellant’s] Unapplied Credit against her [Philadelphia] Tax liability? Zilka v. Tax Rev. Bd. City of Phila. , 281 A.3d 1029 (Pa. 2022) (order).[ J

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U.S. 641 (1994) (holding that Missouri’s use tax scheme impermissibly discriminated against interstate commerce in certain localitie s in which the use tax exceeded the sales tax), the United States Supreme Court endorsed the notion that federal constitutional restraints on state and local taxation of cross

- border economic activity must be evaluated in light of the state’s tax scheme in its entirety. Appellant asserts that, more recently, in Wynne , the high Court made no distinction between state and local taxes, as it determined that, “[i]n applying the dormant Commerce Clause, they must be considered as one.” Appellant’s Brief at 13 (emphasis omitted) (quoting Wynne , 575 U.S. at 564 n.8). Relatedly, App ellant proffers that appellate courts in West Virginia, Colorado, and Arizona have found that state and local tax schemes must be considered in tandem under the Commerce Clause. Appellant notes that the West Virginia Supreme Court invalidated a tax scheme in which the state failed to grant credit against its state

- level use tax for local sales taxes paid out of state

. See Matkovich v. CSX Transp. Inc. , 793 S.E.2d 888 (W. Va. 201 6 ) . Appellant highlights that, in doing so, the Matkovich court “evaluated al l of the taxes at issue at the state level

– regardless of whether they were imposed by a state or locality.” Appellant’s Brief at 14. Similarly, Appellant posits that, in Gen eral Motors Corp. v. City & C ounty of Denver , 990 P.2d 59 (Colo. 1999) , the Col orado Supreme Court invalidated a Denver tax scheme which did not provide credit for sales and use taxes paid to other states and their subdivisions. Appellant stresses that, in deeming the tax scheme unconstitutional, the General Motors court explained: “ Internal consistency requires that states impose identical taxes when viewed in the aggregate

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as a collection of the state and sub

- state taxing jurisdictions. In other words, the interstate taxpayers should never pay more sales or use tax than the int rastate taxpayer.” Id. at 69. Appellant also suggests that Ariz ona Dep artmen t of Revenue v. Ariz ona Pub lic Serv ice Co. , 934 P.2d 796 (Ariz. Ct. App. 1997) , supports her position that state and local taxes[ J

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must be considered together, as, therein, the Ari zona Court of Appeals held that “ [t] he derivative relationship between a state and its counties means that when a county imposes a tax, it does so pursuant to a delegation of state tax authority.” Id. at 799. Moreover , Appellant submits that our Court ’s j urisprudence supports her construction of the dormant Commerce Clause and the need to aggregate state and local taxes thereunder. In that regard, Appellant cites to Philadelphia Eagles Football Club, Inc. v. City of Philadelphia , 823 A.2d 108 (Pa. 2003) ( OAJC) (“ Philadelphia Eagles ”) , and, with little additional analysis, claims that, in that case, we required “[a]pportionment of a local tax . . . as a result of the state taxes in the other states to which the [Philadelphia Eagles] [t]eam was subject

. ” Appellant’s Brief at 16 (emphas is omitted) . Appellant similarly avers that, in Northwood Construction Co. v. Township of Upper Moreland , 856 A.2d 789 (Pa. 2004), we “held that the Commerce Clause mandated that the Township of Upper Moreland . . . apportion the taxpayer’s receipts deriv ed from its Maryland, Delaware, and New Jersey construction activities,” requiring apportionment for “state taxes, not any local tax.” Appellant’s Brief at 16

- 17. Additionally, Appellant contends that the Commonwealth Court endorsed an analysis which rel ates local tax to state tax in Upper Moreland Township v. 7

- Eleven, Inc. , 160 A.3d 921 (Pa. Cmwlth. 2017), wherein the intermediate court “held that the Commerce Clause mandated that the [t]ownship apportion the taxpayer’s receipts derived from its Pennsyl vania franchisees because much of the activities supporting the Pennsylvania franchisees were performed in Texas, the company’s headquarters, or elsewhere outside of Pennsylvania.” Appellant’s Brief at
17 . According to Appellant, these three cases demons trate that our Court and the lower court “have consistently recognized that a Commerce Clause analysis must examine the local tax as it relates to the state tax.” Id. at 17 (emphasis original).[ J

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Appellant next argues that “Philadelphia is part of Pennsyl vania and is subject to the laws and restrictions imposed upon it by Pennsylvania

. ” Id. at 19. To that end, Appellant observes that, “unless authorized by state statute, Philadelphia does not have the power to impose any tax.” Id. (emphasis omitted) . I ndeed, Appellant asserts that , because the City derives its authority to impose taxes by way of state statute, 6 its “ ability to assess and collect any tax, including the [Philadelphia] Tax, is at the absolute behest of Pennsylvania.” Id. at 20. Thus, Appellant insists that we must examine the state and

6 Appell ant notes that the City obtained its right to self

- governance via the First Class City Home Rule Act, 53 P.S. § 13101 et seq ., which precludes the City from enacting taxes without an express grant of authority from the General Assembly, see id. § 13133(a)( 8). Appellant further explains that the City procured the right to impose the Philadelphia Tax by way of the Sterling Act, id. § 15971, which provides, in relevant part:

From and after the effective date of this act, the council of any city of the first class shall have the authority by ordinance, for general revenue purposes, to levy, assess and collect, or provide for the levying, assessment and collection of, such taxes on persons, transactions, occupations, privileges, subjects and personal prop erty, within the limits of such city of the first class, as it shall determine, except that such council shall not have authority to levy, assess and collect, or provide for the levying, assessment and collection of, any tax on a privilege, transaction, su bject or occupation, or on personal property, which is now or may hereafter become subject to a State tax or license fee. Id. Appellant also highlights that the General Assembly carved out a savings clause in the PIT, expressly permitting the City to impo se the Philadelphia Tax:

Notwithstanding anything contained in any law to the contrary, including but not limited to the provisions of

. . . the Sterling Act, the validity of any ordinance or part of any ordinance or any resolution or part of any resolut ion, and any amendments or supplements thereto now or hereafter enacted or adopted by any political subdivision of this Commonwealth for or relating to the imposition, levy or collection of any tax, shall not be affected or impaired by anything contained i n this article

. . . . 72 P.S. § 7359(a) (internal footnote omitted).[ J

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local tax burdens placed upon her simultaneously to determine whether the City violated the dormant Commerce Clause in imposing upon her the Philadelphia Tax, while declining to afford her credit against that tax for her DIT liability. Pivoting to the Complete Auto test, Appellant avers that the City’s tax practice discriminates against interstate commerce, renewing her contention that she has been subject to double taxation, as her tax burden was 1.93% higher than her intrastate counterparts. Appellant argues that the City’s “partial

- credit practice , ” as she phrases it, discriminates against interstate commerce by imposing a tax burden on cross

- border activity which “exceeds the tax burden that [ the City] imposes upon commercial activity that takes place solely within Pennsylvania.” Id. at 30

- 31. In Appellant’s view, it matters
not that she chose to work in Delaware , rather than Pennsylvania , because taxpayers who ch o ose to work in Pennsylvania received a lower tax rate than she did . In this vein, Appellant concludes that “any tax scheme which encourages a taxpayer to conduct intrastate activities instead of interstate activities unconstitutionally burdens interstate commerce.” Id. at 31 (citat ions omitted)

. With respect to the fair apportionment prong of the Complete Auto test, Appellant contends that the City’s tax practice fails “because it does not provide a mechanism to mitigate the risk of duplicative taxation for income earned from interstate commerce,” thus flouting “the constitutional restriction limiting a [state’ s] taxing powers.” Id. at 33 (citation omitted). In this regard, Appellant correctly acknowledges that, under the internal consistency test, we must “assume that every state/local government enacts the same tax regime,” and determine “whether such hypoth etical harmonization imposes a greater burden upon interstate commerce than is imposed upon intrastate commerce.” Id. at 36 (citing Goldberg v. Sweet , 488 U.S. 252, 261 (1989)). Nevertheless, instead of applying the internal consistency test in this manner
— i.e. , assuming that all states and local[ J

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jurisdictions adopt the same tax rates and tax crediting systems as the Commonwealth and the City

— Appellant merely hypothesizes that the taxing jurisdictions adopt the same systems of providing credit, bu t maintain their own differing tax rates. In so doing, Appellant opines that the City’s taxation scheme is internally inconsistent, proclaiming : “if every [s]tate or locality adopted [the City’s] tax practice, interstate income would be subjected to mult iple taxation nationwide.” Id. at 38. Appellant likewise avers that the City’s tax scheme is not externally consistent, as the City taxed her income generated in Wilmington , despite the fact that she had conducted no business in Philadelphia. In essenc e , Appellant asserts that she was taxed merely because she lived in the City , with no legitimate nexus between her economic activity conducted in Wilmington and the City to justify imposition of the Philadelphia Tax

. According to Appellant , “[i]t is clear that taxing Appellant’s income, where none of it is earned in Philadelphia, is disproportionate to the business (or lack thereof) transacted by Appellant in Philadelphia.” Id. at 40. Appellant suggests that Philadelphia Eagles , Northwood Construction , a nd 7

- Eleven establish that a locality may not impose a tax upon 100% of a taxpayer’s activity when such activity did not occur in that locality. While she acknowledges that, here, the City granted a tax credit representing the Wilmington Tax, Appellant co ntends that the City nonetheless “subject[ed] 69% of [her] income to [the Philadelphia ] Tax for work performed entirely outside of the state.” Id. at 43 (emphasis omitted). Finally, Appellant discounts the Commonwealth Court’s conclusion that her residency in the City is reason enough to justify imposition of the Philadelphia Tax , arguing : All states and localities, including Philadelphia, can mee t the

fair apportionment requirement by imposing taxes upon their residents the same way they tax their non

- residents

– by taxing only income generated in Philadelphia, and allowing other jurisdictions to impose their own taxes upon income generated elsewh ere. Alternatively, states and localities can[ J

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- 16 choose to tax all of their residents’ income regardless of where earned, but provide credits for income taxes paid elsewhere. But whichever system is chosen, it must be fair, a n d it must attempt to allocate t he tax based upon where the economic activity occurs, [ i.e. ,] where the income is generated . [The City’s] practice makes no such effort. Id. at 45

- 46 (emphasis original). Appellant , thus, concludes that, “[w]hile [the City] may have the jurisdiction to t ax all of Appellant’s income, that does not mean its ability to do so does not violate the Commerce Clause.” Id. at 47. 7 The City counters by first emphasizing that , contrary to Appellant’s assertions, our Court has , in the past , distinguished state taxe s from local taxes. See McClelland v. City of Pittsburgh , 57 A.2d 846, 848 (Pa. 1948) (“State taxes stand on a different basis from local levies; the former are essential to the very ‘preservation’ of the state itself, while the latter are authorized or p ermitted by the state, not for its actual preservation, but merely to maintain the machinery of local government.” (citation and internal citation omitted)); Nat’l Biscuit v. City of Phila. , 98 A.2d 182, 186

- 87 (Pa. 1953) (finding that a tax administered e ntirely for the benefit of a municipality was not a state tax, but a local tax);

7 The American College of Tax Counsel (“ACTC”) submitted an amicus brief in support of Appellant, agreeing with her position that, by refusing to grant her full credit for her DIT liabi lity , the City is taxing Appellant at a higher rate than it would if she was a Philadelphia resident working entirely in Philadelphia, thus burdening her participation in interstate commerce. In so reasoning, ACTC proffers that, under Wynne , the City was required to give Appellant a credit for her excess DIT to offset the Philadelphia Tax , claiming that the Philadelphia Tax is indistinguishable from the “county” tax which was at issue in Wynne , given that municipal governments are “nothing more than creatu res of the state.” ACTC’s Brief at 9. Relatedly, ACTC proffers that, because state and local taxes must , in its view, be considered as one , the lower court erred in finding that Appellant was subjected to a higher tax rate simply as a result of her choic e to work in Delaware, which has a higher state tax rate. According to ACTC, “it is not Delaware’s responsibility to provide a credit, but rather Pennsylvania and Philadelphia, who are imposing a tax upon income earned elsewhere by their residents.” Id. at 11. ACTC argues that, here, the City should have credited the Wilmington Tax and the remainder of the DIT which did not offset the P IT against Appellant’s Philadelphia Tax liability , in order to place Appellant on “the same tax liability as

. . . a Pennsylvania resident with the same income who worked solely in Philadelphia.” Id. at 13.[ J

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F. J. Busse Co. v. City of Pittsburgh , 279 A.2d 14, 18 (Pa. 1971) (determining that a local tax was not duplicative of the state tax). The City asks our Court to uphold this view, stressing that the Philadelphia Tax is a local tax which was enacted via an ordinance passed by Philadelphia’s City Council, and is administered, collected, and distributed by the Department solely for the benefit of the City and its citizenry. Indeed, the City argues that a municipality’s status as a creature of the state

— and its attendant authority to impose only such taxes as are permitted by the Commonwealth

— “in no way converts a purely local tax into a state tax

. ” City’s Brief at 14. I n the City’s summation, “the [d]ormant Commerce Clause does not require the City of Philadelphia to subsidize Delaware’s decision to impose a higher tax rate on [Appellant] than the Commonwealth of Pennsylvania.” Id. at 17. Critically, t he City contends that Appellant has failed to provide any case law which actually supports her argument that state and local taxes must be assessed unitarily for dormant Commerce Clause purposes . In that regard, the City maintai ns that Appellant misconstrues Philadelphia Eagles , Northwood Construction , and 7

- Eleven , as, according to the City, those decisions merely affirmed that localities imposing taxes must satisfy the requirements of the dormant Commerce Clause , including by providing credit for taxable activity which occurred outside of the taxing jurisdiction , which the City stresses that it did here

. The City expounds that, in that trio of cases, this Court and the Commonwealth Court “did not address whether local taxes and state taxes must be aggregated because tha t question was not before any of the Courts.” City’s Brief at 18 (emphasis omitted)

. Moreover, t he City asserts that Appellant persistently misinterprets Wynne , as , therein, the high Court did not find Maryland’s tax scheme unconstitutional on the basis that state and local taxes must be considered in tandem, but, rather, it condemned Maryland’s tax scheme because Maryland’s “county” tax was actually a duplicative state[ J

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tax against which the state refused to offer credit for out

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- state taxes paid. T he City , thus, maintains that the manner in which the “county” tax functioned ( i.e. , it was enacted by the state legislature and administered, collected, and distributed by Maryland’s Comptroller) rendered it a state tax in disguise , whereas the Philade lphia Tax is a purely local tax which is administered, collected, and distributed by the Department , and was enacted by the Philadelphia City Council

. Contemplating Appellant’s claim that she was subjected to double taxation , the City argues that the Depar tment provided Appellant a full credit for income taxes paid to Wilmington, leading her to incur only the same 3.922% Philadelphia Tax rate as a Philadelphia resident working entirely in Philadelphia. From the City’s perspective , the flaw in Appellant’s d ouble taxation claim is palpable “when you consider what the outcome would be if neither Wilmington nor Philadelphia had an income tax and [Appellant] was only subject to Delaware and Pennsylvania income taxes.” Id. at 22. Specifically, the City points o ut that, under such circumstances , Appellant would be taxed at Delaware’s rate of 5% and would receive a credit from Pennsylvania equal to its tax rate of 3.07%, such that Appellant would still incur a tax rate that is 1.93% higher than her in

- state cohort s ( namely , Delaware’s full 5% ). The City emphasizes that this scenario would present no dormant Commerce Clause violation, as Pennsylvania would not be expected to issue a further refund to account for Delaware’s higher tax rate. In the City’s view, then, “[t]he Commonwealth Court correctly applied the same logic to the instant matter and found that there was no double taxation because ‘[Appellant] never pays more than one local tax or more than one state tax.’” Id. at 23 (quoting Zilka , 1063

- 1064 C.D. 2019, at 5). The City next addresses the Complete Auto test , preliminarily suggesting that the two prongs thereof which are r elevant in this case (specifically , the discrimination and fair[ J

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apportionment prongs) address the same issue

— the risk of double taxation. To that end, the City asserts that the discrimination prong of the test is subsumed by the fair apportionment prong , as the former prevents states from “discriminat[ing] against interstate commerce either by providing a direct commercial advantage to local business, or by subjecting interstate commerce to the burden of ‘ multiple taxation, ’ ” Nw. States Portland Cement C o. , 358 U.S. at 458 (citations and internal citations omitted) , while the latter ensures that “there is no danger of interstate commerce being smothered by cumulative taxes of several states,” Complete Auto , 430 U.S. at 277. The City contends that, here, there is no risk of double taxation, as the Philadelphia Tax meets both the internal and external consistency tests of the fair apportionment prong of Complete Auto

. Maintaining that the Philadelphia Tax is internally consistent, the City reasons that all taxpayers would face the same local income tax rate of 3.922% if every local taxing authority in the nation imposed Philadelphia’s taxation scheme

— collecting wage taxes on income earned by residents wi thin the jurisdiction and on income earned by residents working outside of that taxing authority’s jurisdiction, but allowing the latter a credit against their local wage taxes for wage taxes paid to out

- of

- state local taxing authorities. Furthermore, the City argues that the result remains the same when the analysis is expanded to assume that all states adopt Pennsylvania’s state income tax rate of 3.07%, as well as its practice of providing credit against an individual’s income tax liability for income t axes paid out

- of

- state. Critically , the City contends that Appellant “continues to offer a distorted version of the internal consistency test” in reaching her conclusion that the Philadelphia Tax is unconstitutional, City’s Brief at 28, as she utilized a hypothetical scenario in which every taxing jurisdiction adopts a different tax rate , as opposed to the correct hypothetical in which every taxing jurisdiction adopts the same practice and the
same tax rate , id. at 32. Thus, according to the City, “[w]hen the internal consistency test[ J

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is applied correctly

– using identical tax rates

– Philadelphia’s (and Pennsylvania’s) [income tax] schemes satisfy the internal consistency test.” Id. Likewise , t he City claims that its tax scheme is externally consistent, as the City has authority to tax all of Appellant’s income, wherever earned, based on her domicile in Philadelphia. See Okla. Tax. Cmm’n v. Chickasaw Nation , 515 U.S. 450, 463 (1995) (“Domicile itself affords a basis for . . . taxation.”). In any event , the City asserts that it “negates any claim of unfair apportionment or double taxation” by “provid [ing] a credit for a resident’s out

- of

- state activity

. ” City’s Brief at 33 (citing, inter alia , House of Lloyd v. Commonwealth , 684 A.2d 213, 217 (Pa. Cmwlth. 1996) (“The Commonwealth’s use tax is fairly apportioned in that it includes the customary provisions against duplication, including a credit for sales tax paid to another state.”); Goldberg , 488 U.S. at 264 (“The

.

. . tax ing scheme is fairly apportioned, for it provides a credit against its use tax for sales taxes that have been paid in other States.” (ellipses original) )). Lastly, t he City maintains that Philadelphia Eagles , Northwood Construction , and 7

- Eleven do not su pport Appellant’s argument that the full credit she received for her Wilmington Tax is insufficient to satisfy the external consistency test. Indeed, the City contends that this trio of cases is distinguishable from the instant matter because, in each of those cases, “the offending jurisdiction failed to give any credit for taxes paid to another jurisdiction,” id. at 34, whereas, here, “the City provided full credit for any out

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- jurisdiction activity, satisfying the external consistency test,” id. at 35. Accordingly, in light of the foregoing, the City asks our Court to affirm the decision of the court below. 8

8 The Pennsylvania Department of Revenue (“PDOR”) submitted an amicus brief in support of the City. Therein, PDOR avers that th e Commonwealth Court properly applied the Complete Auto test and found this matter distinguishable from Wynne

. Countering Appellant’s Complete Auto assessment, PDOR argues that the City’s tax scheme meets the internal consistency test because, unlike the Maryland tax scheme in Wynne , the City offsets the Philadelphia Tax by granting resident s credit for taxes paid to other local (continued...)[ J

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jurisdictions, such as Wilmington. In that regard, PDOR emphasizes that, if the Philadelphia/Pennsylvania tax scheme was applied in every jurisdiction, no resident would ever be subject to double taxation, thus demonstrating internal consistency. PDOR explains that any heightened tax burden on Appellant versus that incurred by her intrastate peers stems from the interaction of two different

— but nondiscriminatory

— tax schemes, which is permissible under the dormant Commerce Clause. PDOR next highlights that, while the external consistency test has been employed by the high Court in corporate tax cases and sales tax cases, Wynne presented the Court with the first opportunity to apply the test in the context of a resident

- based individual income tax, but the Court declined to do so, finding that the tax in question failed the internal consistency test. Moreover, PDOR notes that t he Wynne Court “endorse[d] the ability of a resident state to tax all of its resident’s income , so long as it does not run afoul of the internal consistency test. ” PDOR’s Brief at 14 (emphasis omitted ) (citing Wynne , 575 U.S. at 566

- 68). Hence, PDOR conc ludes that “there is no clear holding in Wynne that a residence

- based income tax must be externally consistent.” Id. at 15. PDOR additionally directs our Court to Justice Ginsburg’s dissenting opinion in Wynne , and the hypothetical “fix” she offered

— s pecifically, Justice Ginsburg suggested that Maryland could amend its tax code to eliminate the special non

- resident tax and simply continue taxing all residents’ income regardless of source, Wynne , 575 U.S. at 582 (Ginsburg, J., dissenting)

— with which t he Wynne majority ultimately acquiesced, see id. at 568

- 69 (majority opinion). PDOR explains that, in its view, the Wynne Court could not have envisioned applying the external consistency test in the context of a resident

- based individual income tax, as t his “fix” would indubitably fail the test. PDOR submits that a recent Utah Supreme Court decision, Steiner v. Utah State Tax Comm ’ n , 449 P.3d 189, 197 (Utah 2019) (opining that the Wynne Court “strongly implied that tax systems that fail external consistency would nonetheless pass constitutional muster”), underscores its reasoning in this regard. In any event, PDOR agrees with the Commonwealth Court’s determination that the Philadelphia Tax is externally consistent because the City provide s its residents with tax credit for wage taxes paid to outside jurisdictions and , in so doing, does not tax more than its fair share of resident s’ income. In PDOR’s view, the City “is economically just ified [in] taxing a resident on all of his income because residents receive all of the protections and benefits afforded by the resident jurisdiction, e.g. , fire, police, public utilities.” PDOR’s Brief at 18. Lastly, PDOR avers that our Court’s adoption of Appellant’s argument would detrimentally impact state and local tax revenues “without any clear indication from the U.S. Supreme Court that such a result is mandated.” Id. at 19. PDOR submits that Appellant ’s argument, if adopted, would require “the Commonwealth and its political subdivisions, which have lower tax rates, to export their tax revenues to bordering states and jurisdictions with higher tax rates, ” thus threatening “ the Commonwealth’s ‘ fiscal wel l

being ’” and encouraging our government “to increase its tax rates to keep from losing (continued...)[ J

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- 22 IV. Analysis As an initial matter, we emphasize that the question of aggregation for purposes of a dormant Commerce Clause analysis is a matter of first impression for this Court. To that end, we reject Appellant’s assertion that Philadelphia Eagles , Northwood Construction , and 7

- Eleven demon strate that this Court and the Commonwealth Court

“ have consistently recognized that a Commerce Clause analysis must examine the local tax as it relates to the state tax. ” Appellant’s Brief at 17 (emphasis original). I n this trio of cases , neither our Co urt nor the lower court pronounced that local and state taxes must be aggregated in conducting a Complete Auto analysis under the dormant Commerce Clause ; thus, these cases do not control our initial query

. 9 Instead, we place paramount importance on the high Court’s decision in Wynne , which we find to be instructive on the question of aggregation . Based thereon, we find that, in addressing Appellant’s dormant Commerce Clause challenge, we must examine the circumstances surrounding the Philadelphia Tax in order to determine whether it is truly a local tax or is, instead, a state tax masquerading as a local tax. As noted , in Wynne , the high Court found that Maryland’s “county” tax was essentially little more than a state tax masquerading as a local tax, g iven that the state imposed the tax via state legislation and the state’s comptroller collected the tax. See Wynne , 575 U.S. at 546. In our view , the Court’s logic and characterization of the county tax as a state tax based on the circumstances underlying its creation and the manner of its collection via the state’s comptroller reveal that state and local taxes need not be

revenue to other states.” Id. at 21. Accordingly, PDOR urges our Court to affirm the decision of the Commonwealth Court.

9 We similarly find that Lohman , supra , is no t relevant to our consideration of this issue, as it does not address the need, vel non , to aggregate state and local taxes in a dormant Commerce Clause analysis.[ J

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aggregated for purposes of a dormant Commerc e Clause analysis , as Appellant contends. In deed , nowhere in its comprehensive opinion did the Wynne Court endorse the notion that local taxes are essentially a legal fiction , indistinguishable from state taxes. Rather , in our view, the Court sanctioned an ad hoc approach, under which a “local” income tax may be deemed indistinguishable from the corresponding state’s income tax only if, like Maryland’s “county” tax, it is actually a duplicative state tax in disguise. Here, the Philadelphia Tax is readil y distinguishable from the county tax at issue
in Wynne , as the latter was enacted by the State of Maryland and collected by Maryland’s comptroller, whereas the Philadelphia Tax was enacted by Philadelphia’s City Council and is collected by the City’s Depa rtment of Revenue solely for the benefit of the City and its citizenry

. In light of this stark contrast , we reject Appellant’s argument that Wynne mandates that we aggregate the Philadelphia Tax with the PIT in discern ing whether it violates the dormant C ommerce Clause , as her view in that regard is contrary to the high Court’s teachings in Wynne

. We likewise reject Appellant’s claim that the City was required to aggregate the Philadelphia Tax and the PIT because local governments, such as the City, are creatures of statute, which derive taxation authority solely from the legislative enactments of our General Assembly. It is axiomatic that “[t] he validity of the taxing ordinance does not depend upon wheth er the tax is regarded in a legal sense as a state or local tax ,” given that “[a] ll taxes in Pennsylvania levied by municipal and quasi municipal corporations must, of course, be authorized by the legislature. ” McClelland , 57 A.2d at 848. Indeed, our Cou rt has recognized that, “ [i]n that sense , therefore, all [taxes] may be considered
state taxes. ” Id. (emphasis original). Nevertheless , although our Court has acknowledged that, in a sense , state and local taxes are indistinguishable, as both are authori zed by state legislation, we have also stressed that “[s]tate taxes stand on a[ J

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different basis from local levies.” Id. In that vein, we have highlighted that state taxes “are essential to the very ‘preservation’ of the state itself,” whereas local taxes “are authorized or permitted by the state, not for its actual preservation, but merely to maintain the machinery of local government.” Id. (internal citations omitted) ; see Nat’l Biscuit , 98 A.2d at 186 (observing that , in McClelland , we concluded that “ a tax imposed for the benefit merely of a local political subdivision, and not for general State purposes, is not to be regarded as a State tax ”). Thus, nothing in the high Court’s teachings, nor in our own jurisprudence, stand s for the pr emise that state and local taxes are broadly indistinguishable, much less support s Appellant’s conclusion that state and local taxes
must be aggregated for purposes of a dormant Commerce Clause analysis

. Aside from her reliance on Wynne , which, as explain ed above , undermines her argument in favor of aggregation , and Philadelphia Eagles , Northwood Construction , and
7

- Eleven , which are inapposite to the issue, Appellant provides little else to justify her view that we must consider the Philadelphia Tax in ta ndem with the PIT in addressing her dormant Commerce Clause challenge. In her final effort to sway this Court with respect to the question of aggregation, Appellant proffers three out

- of

- state cases
— Arizona Public Service , supra ; General Motors , supra ; and Matkovich , supra . In the first of these cases, an Arizona court of appeals held that an Arizona public utility company which purchased coal from a mine located in McKinley County, New Mexico, was entitled to tax credits, against the amount it p aid in Arizona’s use tax, for gross receipts taxes which the company paid to both New Mexico and McKinley County. In so concluding, the Arizona court of appeals examined A.R.S. § 42

- 1409, 10 which governed the state’s use tax and provided an express exempt ion whereby the use tax did not apply to “[t]angible personal

10 Section 42

- 1409 was renumbered following the court’s decision in Arizona Public Service.[ J

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property the sale or use of which has already been subjected to an excise tax at a rate equal to or exceeding the tax imposed by this article under the laws of another state of the United States .” Id. § 42

- 1409(A)(2). The provision further provided that, “[i]f the excise tax imposed by the other state is at a rate less than the tax imposed by this article, the tax imposed by this article is reduced by the amount of the tax already imposed by
th e other state.” Id. The court found that the plain language of the statute

— crediting a taxpayer for excise taxes paid on personal property “under the laws of another state” to offset Arizona’s use tax

— required it to exempt the utility company from th e use tax for the gross receipts taxes paid to both the State of New Mexico and McKinley County. With respect to the latter taxing authority, the court observed that the county was entitled to impose its gross receipts tax on taxpayers solely by virtue of its “derivative relationship” with the state, and, more precisely, from the state’s enabling statutes. Ariz. Pub. Serv. Co. , 934 P.2d at 799. Tellingly, however, the court concluded that this relationship between the state and county revealed that the w ord “under,” as employed by Arizona’s legislature in Section 42

- 1409(A)(2), was unambiguous and justified an exemption for the gross receipts tax which the utility company paid to McKinley County. While the Arizona intermediate court briefly mentioned th e Commerce Clause in its disposition of the tax issue before it, its focus, undoubtedly , was on the language of its state’s legislation, and it is that legislation which governed the outcome of the case. As such, Arizona Public Service does not support th e novel practice of aggregating state and local taxes for purposes of a dormant Commerce Clause analysis. Likewise, General Motors is of limited value. Therein, the Colorado Supreme Court was tasked with determining whether a use tax imposed by the City and County of Denver violated the dormant Commerce Clause. In finding that it did, the court preliminarily concluded that “[i] nternal consistency [under Complete Auto ] requires that states impose[ J

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identical taxes when viewed in the aggregate

— as a collec tion of state and sub

- state taxing jurisdictions .” General Motors , 990 P.2d at 69. Markedly, this brief conclusory statement represents the entirety of the court’s reasoning, or lack thereof, underlying its determination that state and local taxes must b e aggregated for consideration under the dormant Commerce Clause. Thus, General Motors provides a poor basis on which for our Court to declare, for the first time, that state and local level taxes are one and the same for purposes of the Commerce Clause. 11

11 Notably, the General Motors court also erroneously employed the Complete Auto test. Specifically, in attempting to discern whether Denver’s taxation scheme was int ernally consistent, the court provided the following hypothetical scenario:

[I]f Colorado imposed a 1% sales or use tax and Denver a 2% tax, a purchaser or user would owe a 3% total tax. Similarly, if Michigan collected a 2% sales or use tax and Detroit a 1% tax, a purchaser or user in Detroit would pay a 3% total tax. However, a user who purchased the item in Detroit would be subject to an additional 1% tax upon the storage or use of the item in Denver because section 53

– 92(c) only credits taxes paid to other municipalities. Thus, Denver’s use tax could burden interstate commerce if every other state and municipality employed the same tax structure as Colorado and Denver, but imposed different tax rates. General Motors , 990 P.2d at 70. This is an inaccu rate application of the internal consistency test, as the Colorado Supreme Court invented a scenario with “similar” tax schemes in Colorado and Michigan, but with differing rates of taxation, and which are inverted such that Colorado’s tax rate matched tha t of Detroit, and Michigan’s tax rate matched the rate imposed by Denver. The court was correct that this scenario could have led to double taxation, as an individual who purchased an item in Detroit would have received a 1% credit against his or her Denv er tax, leaving 1% remaining. Based on its view in this regard, the court reasoned that Denver’s tax structure was “internally inconsistent because Denver’s credit mechanism could cause multiple taxation even if every state and municipality were to impose a taxing scheme similar to the one present in Colorado and Denver.” Id. at 69 (emphasis added). Yet, the internal consistency test does not operate, as the Colorado Supreme Court suggest ed , in terms of “similar taxes.” Rather, the appropriate question , which we address below, is whether an individual would be subject to double taxation if all states and local taxing authorities were to adopt the same taxes and crediting systems as Pennsylvania and Philadelphia. See Wynne , 575 U.S. at 562 (“This test, which helps (continued...)[ J

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The third and final out

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- state case on which Appellant relies, Matkovich , also provides negligible support for her claim that state and local income taxes must be viewed as one under the dormant Commerce Clause. In Matkovich , the West Virginia Supre me Court concluded that a tax credit statute, W. Va. Code § 11

- 15A

- 10a, which operated to offset the state’s motor fuel use tax, violated the dormant Commerce Clause because the state’s tax department applied the statute in a manner which provided a taxpay er credit only for sales taxes paid on fuel to other states and not for such taxes paid to cities, counties, and localities of other states. Relying on Wynne , Arizona Public Service , and General Motors , the court found that proper application of the statute entitled taxpayers to receive sales tax credits for sales taxes paid to other states and to subdivisions of other states. In so doing, the court opined that “[a] ny other construction of th [e] statute would invariably violate the Commerce Clause ’ s prohibition on subjecting interstate transactions to a greater tax burden than that imposed on strictly intrastate dealings. ” Matkovich , 793 S.E.2d at 897. We are unpersuaded by Matkovich , given that the court therein derived support for its conclusion f rom Arizona Public Service , which, as discussed, is distinguishable from the instant case, and from General Motors , which, as noted, concluded that state and local taxes must be aggregated without citing any authority or undertaking any semblance of a subs tantive analysis with respect to the issue. Moreover, we find that the Matkovich court’s ruling contravenes the high Court’s reasoning in Wynne , which, as explained, requires an ad hoc assessment of the local income tax scheme at issue to discern whether it is distinct from the corresponding state income tax or indistinguishable therefrom for purposes of a Complete Auto analysis.

courts identify tax schemes that discriminate against interstate commerce, looks to the structure of the tax at issue to see whether its identical application by every State in the Union would place interstate commerce at a disadvantage as comp ared with commerce intrastate.” (emphasis added; citations and internal quotation marks omitted)).[ J

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Thus, Appellant has failed to persuade us that her construction of the dormant Commerce Clause aligns with Wynne , and these th ree out

- of

- state cases do not sway us in her favor. Accordingly, consistent with Wynne , we conclude that the Philadelphia Tax was enacted , and operates , as a purely local tax, given that it was promulgated by Philadelphia’s City Council and is collected b y the Department for the sole benefit of the City and its residents ; as a result, we will not consider these state and local taxes i n the aggregate in applying the Complete Auto test. H aving determined that the Philadelphia Tax and the PIT should be treated as discrete taxes, we must consider whether the City’s tax scheme discriminates against interstate commerce. We conclude, as did the Commonwealth Court, that the Philadelphia Tax and the City’s corresponding crediting system satisfy the test set f orth
in Complete Auto

. As explained above, Appellant challenges the Philadelphia Tax under two prongs of the Complete Auto test: first, she contends that the City’s tax scheme is not fairly apportioned; and second, she avers that the tax scheme discriminates against interstate commerce. In assessing whether the tax scheme is fairly apportioned, we must determine whether it is internally and externally consistent. Once more, t he high Court’s decision in Wynne provides clear guidance with respect to this endeavor. To briefly reiterate , the Wynne Court found that Maryland’s tax scheme was not internally consistent because, i f every state adopted the three taxes at issue (the county tax, the state tax, and the special non

- resident tax) and adopted Maryland’s system of not crediting against those taxes, residents who paid income tax to out

- of

- state jurisdictions would incur dou ble taxation. Wynne , 575 U.S. at 56 5

. The Court stressed that such double taxation was “not simply the result of [the tax scheme’s] interaction with the taxing schemes of other States,” but, instead , emanated from inherent discrimination contained[ J

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within the scheme

. Id. (citations omitted). Pertinently , in declaring Maryland’s tax scheme unconstitutional, the Court explained that “Maryland could remedy the infirmity in its tax scheme by offering, as most States do, a credit against income taxes paid to other States ,” which would vindicate the tax scheme under the internal consistency test. Id. at 568 (citation omitted). In accordance with Wynne , we must now determine whether the City’s tax scheme is internally consistent . To do so, we must assume that all local taxing jurisdictions adopt the Philadelphia Tax rate of 3.922% and the City’s corresponding practice of crediting taxpayers for local taxes paid to other jurisdictions. In this scenario, April, who lives in State A and works exclusively in State A, would pay 3.922% once to State A, while Bob, who lives in State A but works in State B, would also pay only 3.922% once, to State B, because State A would permit him a credit against its own tax. Thus, both in

- state and
out

- of

- state taxpayers would yi eld the same tax obligation. The same remains true even if we add the Commonwealth’s state tax to this hypothetical, as each taxpayer would simply incur an additional state tax obligation of 3.07% consistent with the PIT and the Commonwealth’s correspondi ng practice of offsetting the PIT with state taxes paid elsewhere. Accordingly, when the internal consistency test is properly applied to the Philadelphia Tax and the PIT, along with the corresponding tax credits permitted by the City and the Commonwealth , it is evident that any remaining “ disparate incentives to engage in interstate commerce ” stem solely from “ the interaction of two different but nondiscriminatory and internally consistent schemes .” Id. at 562 (citations omitted); see Steiner , 449 P.3d at 197 (finding that, because Utah offered a tax credit for out

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- state taxes, it was internally consistent and compatible with Wynne ); Goggin v. State Tax Assessor

, 191 A.3d 341, 347 (Me. 2018) (“ Here, th e Maine statute expressly allows a[ J

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credit for the payment of individual income taxes to other states

. . . and therefore does not run afoul of Wynne

. ”). Hence, the Commonwealth Court correctly determined that any excess taxes paid by Appellant were simpl y the result of Delaware’s higher income tax rate of 5%, rather than any inherent discrimination contained in the Philadelphia Tax or the City’s practice of offsetting its tax with credits paid only to local taxing jurisdictions. A simple hypothetical bol sters our conclusion in this regard : If neither Philadelphia nor Wilmington imposed a local wage tax, Appellant would have nonetheless paid 1.93% more in income taxes than her Pennsylvania counterparts who worked solely in the Commonwealth, as the DIT rat e was 5% while the PIT rate was 3.07%. In this hypothetical, Commerce Clause principles would not have required the Commonwealth to credit Appellant beyond the 3.07% which it already permitted her, nor would Delaware incur any similar obligation to lessen Appellant’s tax burden, given that states may set their own income tax rates. Certainly , the City should not be required to subsidize Delaware’s higher tax rate when it already offsets its Wage Tax by crediting taxpayers for analogous local taxes paid ou tside of its jurisdiction. For these reasons, we find that the Philadelphia Tax meets the internal consistency test, and that, relatedly, the tax is not discriminatory under the third prong of the Complete Auto test because the City imposes a consistent t ax on all residents and provides the necessary credit against similar out

- of

- state local taxes paid by them. See Armco Inc. , 467 U.S. at 644 (commingling consideration of the internal consistency test and the discrimination prong of the Complete Auto test because “[a] tax that unfairly apportions income from other States is a form of discrimination against interstate

commerce ”) ; see also City’s Brief at 25

- 26 (advocating that the discrimination and fair apportionment prongs of the Complete Auto test merge)

.[ J

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Additionally, we find that the Philadelphia Tax meets Complete Auto’s external consistency test, which examines “the economic justification for the State ’ s claim upon the value taxed, to discover whether a State ’ s tax reaches beyond that portion of value that is fairly attributable to economic activity within the taxing State.” Jefferson Lines , 514 U.S. at 185. It is well

- established that “domicile in itself establishes a basis for taxation” because the “[e]njoyment of the privileges of residence within the state, and the attendant right to invoke the protection of its laws, are inseparable from the responsibility for sharing the costs of government. ” Lawrence , 286 U.S. at 279. Indeed, “[a] tax measured by the net income of residents is an equitable method of distributing the burdens of government ,” which include public education and emergency services, “ among those who are privileged to enjoy its b enefits .” People of State of N.Y. ex rel. Cohn v. Graves , 300 U.S. 308, 313 (1937). Consequently, we agree with the lower court that “ Philadelphia’s provision of municipal benefits and services to its residents provides sufficient economic justification for the imposition of its Wage Tax.” Zilka , 1063

- 1064 C.D. 2019, at 9 (citation omitted). Moreover, as the lower court explained, “Philadelphia avoided taxing more than its fair share of [Appellant’s] wages by providing a tax credit for 100% of the Wilmi ngton Tax.” Id. Thus, we find that the City’s tax scheme is externally consistent under Complete Auto

. For these reasons , we conclude that the City did not violate the dormant Commerce Clause by imposing upon Appellant the Philadelphia Tax, crediting her for the similar local tax she paid to Wilmington, but declining to afford her an additional credit for the state taxes she paid to Delaware, as the tax scheme is both internally and externally consistent and is not discriminatory against interstate commer ce, in conformance with the Complete Auto test. To hold otherwise would , in effect, nullify the high Court’s venerable recognition that “ tax schemes that create disparate incentives to engage in interstate commerce (and sometimes result in double taxation) only as a result of the interaction of[ J

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two different but nondiscriminatory and internally consistent schemes ” are not unconstitutional. Wynne , 575 U.S. at 562. Accordingly , we affirm the Commonwealth Court’s decision concluding that the tax scheme is constitutional

. Justices Donohue and Wecht join the opinion. Justice Wecht files a concurring opinion. Justice Dougherty files a dissenti ng opinion in which Justice Mundy joins. Justice Brobson did not participate in the consideration or decision of this matter.