UNITED STATES COURT OF APPEALS 

FOR THE TENTH CIRCUIT 

_________________________________ 

UNITED STATES OF AMERICA, 

 Plaintiff–Appellee, 

v. 

CASSLYN MAE WELCH, 

 Defendant–Appellant. 

No. 14–2194 

(D.C. No. 1:10-CR-02734-JCH-3) 

(D. New Mexico) 

_________________________________ 

ORDER AND JUDGMENT*

_________________________________ 

Before BRISCOE, EBEL, and BACHARACH, Circuit Judges. 

_________________________________ 

 

Ms. Casslyn Mae Welch was indicted on eleven counts based on her 

involvement in a carjacking and conspiracy that led to the killing of two 

individuals. Facing a possible death sentence, Ms. Welch signed a plea 

agreement, promising to cooperate with the government’s investigation and 

prosecution of another suspect. Ms. Welch performed her obligations under 

the plea agreement by September 2013. 

 

*

 This order and judgment does not constitute binding precedent except 

under the doctrines of law of the case, res judicata, and collateral estoppel. 

But the order and judgment may be cited for its persuasive value under 

Fed. R. App. P. 32.1(a) and 10th Cir. R. 32.1(A). 

FILED 

United States Court of 

Appeals 

Tenth Circuit 

December 16, 2015

Elisabeth A. Shumaker 

Clerk of Court

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Ms. Welch alleges that roughly two weeks before her sentencing 

hearing, the prosecutor orally promised to do three things: 

1. move for a downward departure based on Ms. Welch’s 

substantial assistance, 

2. “not [to] oppose” Ms. Welch’s request for a 20-year 

sentence, and 

3. defer to the district court on any sentencing decisions. 

The parties do not dispute that the government moved for a downward 

departure. But according to Ms. Welch, the prosecutor breached the plea 

agreement and the implied covenant of good faith and fair dealing by 

1. agreeing to not oppose a 20-year sentence, but saying at 

the sentencing hearing that the government did “not 

concur” with Ms. Welch’s request for a 20-year sentence 

and 

2. agreeing to defer any sentencing decisions to the district 

court, but saying at the sentencing hearing that a 40-year 

sentence was “sufficient but not greater than necessary” 

and that Ms. Welch had made a “decision . . . to kill” and 

lacked a “moral compass.” 

The district court rejected both claims, holding that the government had 

not breached the plea agreement or an alleged covenant of good faith and 

fair dealing. We agree. 

I. The government did not breach any express promises in the plea 

agreement. 

We conclude that the government did not breach any express 

promises in the plea agreement. In our view, the government complied with 

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all of its written promises, and the alleged oral promises were 

unenforceable. 

A. We apply principles of contract law. 

We engage in de novo review of claims that the government breached 

a plea agreement. See United States v. Burke, 633 F.3d 984, 994 (10th Cir. 

2011). In applying this standard, we consider whether Ms. Welch proved a 

breach through a preponderance of the evidence. Sternberg v. Sec’y, Dep’t 

of Health & Human Servs., 299 F.3d 1201, 1206 (10th Cir. 2002). 

To determine whether Ms. Welch satisfied her burden, we conduct a 

two-part inquiry, examining 

1. the nature of the government’s promise and 

2. Ms. Welch’s reasonable understanding of the promise at the 

 time of her guilty plea. 

Burke, 633 F.3d at 994. We interpret the plea agreement based on 

principles of contract law, looking to “the express language in the 

agreement.” United States v. Cudjoe, 534 F.3d 1349, 1353 (10th Cir. 2008) 

(quoting United States v. Rodriguez-Rivera, 518 F.3d 1208, 1212-13 (10th 

Cir. 2008)). But any ambiguities are interpreted against the government as 

the drafter of the agreement. See United States v. VanDam, 493 F.3d 1194, 

1199 (10th Cir. 2007). 

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 B. The government complied with its written promises. 

In the written plea agreement and addendum, the government 

promised to 

1. move to reduce Ms. Welch’s base-offense level by three 

levels under § 3E1.1 of the sentencing guidelines, 

2. move to dismiss two specified counts against Ms. Welch 

if she continued to accept responsibility for her conduct, 

3. refrain from further charges against Ms. Welch for 

conduct underlying the indictment, and 

4. consider moving for a downward departure under § 5K1.1 

of the sentencing guidelines. 

R. vol. I, at 111-12, 115; R. vol. II, at 2-3. 

The parties do not dispute that the government 

1. moved for a three-level reduction in Ms. Welch’s offense 

 level, 

2. moved to dismiss the specified charges against Ms. 

Welch, 

3. did not bring further charges against Ms. Welch, and 

4. moved for a downward departure. 

See R. vol. I, at 121-22; R. vol. II, at 63-72; Oral Arg. at 11:15-12:00. The 

government’s motion for a downward departure proved successful: the 

district court sentenced Ms. Welch far below the floor of the guideline 

range. See R. vol. I, at 209 (reducing Ms. Welch’s sentence from 1,490 

months to 480 months). Thus, the government did everything that it had 

expressly promised in the written plea agreement and addendum. 

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C. The alleged oral promises are unenforceable and did 

 not relinquish the government’s discretion. 

Ms. Welch contends that the prosecutor failed to carry out 

subsequent oral promises. We reject this contention. The alleged oral 

promises are unenforceable because they (1) did not appear in the written 

plea agreement or addendum and (2) lacked consideration from Ms. Welch. 

1. The plea agreement foreclosed oral modification. 

We consider a plea agreement “completely integrated” if it contains a 

“complete and exclusive statement of the terms of the agreement.” United 

States v. Rockwell Int’l Corp., 124 F.3d 1194, 1199 (10th Cir. 1997) 

(quoting Restatement (Second) of Contracts § 210(1) (1981)). The written 

plea agreement and addendum contained both a complete expression of the 

terms and express integration clauses. As a result, the plea agreement was 

completely integrated, precluding any modification unless it was in writing 

and signed by all parties. R. vol. I, at 116; R. vol. II, at 3. The integration 

clauses could be avoided only through proof of “fraud, mistake, duress,” or 

another ground sufficient for setting aside a contract. Blackledge v. 

Allison, 431 U.S. 63, 75 n.6 (1977). 

Rather than invoke these grounds, Ms. Welch argues that the 

government breached its alleged oral promises. But these promises were 

never put in writing or signed by the parties. In the absence of a signed 

writing, the alleged oral promises are unenforceable under the plea 

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agreement because enforcement would create a conflict with the integration 

clauses. See United States v. Cudjoe, 534 F.3d 1349, 1353 (10th Cir. 2008) 

(explaining that we look to the “express language in the [plea] 

agreement”). 

2. The alleged oral promises are not enforceable as a new 

agreement. 

The alleged oral promises are also unenforceable as a new agreement. 

If viewed as a new agreement, the alleged oral promises would have been 

enforceable only if Ms. Welch had provided new consideration. See United 

States v. Leach, 562 F.3d 930, 936-37 (8th Cir. 2009) (explaining that the 

government’s alleged oral promises, which were made after the defendant 

had pleaded guilty, could not serve as “part of the [defendant’s] 

inducement or consideration underlying the guilty plea”); In re Sealed 

Case, 686 F.3d 799, 802-03 (D.C. Cir. 2012) (noting that the government is 

not bound by a promise when it “obtained nothing from [a] promise to 

which it was not already entitled”). But Ms. Welch did not provide any 

new consideration for the alleged oral promises. 

After the parties signed the written plea agreement, Ms. Welch did 

not promise to do anything that she was not already obligated to do. In 

fact, when the government allegedly made the oral promises, Ms. Welch 

had completed her performance under the written plea agreement more than 

seven months earlier. Thus, the prosecutor’s alleged oral promises lacked 

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consideration from Ms. Welch. Without consideration from Ms. Welch, the 

alleged oral promises would be unenforceable as a new agreement. 

The result might be different if the government had induced Ms. 

Welch with the promise of a 20-year sentence and Ms. Welch reciprocated 

by supplying the government with additional help. For example, if the 

government had orally promised to support Ms. Welch’s request for a 20-

year sentence and that promise led Ms. Welch to cooperate with another 

investigation, the oral promise might have been enforceable. See, e.g.,

Gibson v. Arnold, 288 F.3d 1242, 1245 (10th Cir. 2002) (explaining that a 

promisee’s “detrimental reliance” on an oral promise may estop the 

promisor from claiming the oral promise was not enforceable). 

But that was not the case here. The government allegedly promised 

not to oppose a 20-year sentence after Ms. Welch had completed her 

performance. Thus, the government’s alleged oral promises could not have 

induced Ms. Welch’s performance. In these circumstances, the alleged oral 

promises could not be enforced as a separate agreement. 

3. The alleged oral statements did not relinquish the 

government’s discretion. 

Ms. Welch contends that the written agreement “left open” the 

government’s eventual position on sentencing. Based on this open term in 

the written agreement, she argues, the government initially retained 

discretion on what to say at the sentencing hearing. But Ms. Welch argues 

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that the prosecutor then relinquished that discretion by orally agreeing (1) 

not to oppose a 20-year sentence and (2) to defer sentencing decisions to 

the district court. 

We disagree. About two weeks before the sentencing hearing, defense 

counsel asked the prosecutors what position the government intended to 

take at the sentencing hearing. The prosecutors allegedly promised to not 

oppose a 20-year sentence and to defer to the district court’s sentencing 

decisions. But these alleged promises would not have abrogated the 

government’s discretion or “filled in” any open terms. The government 

always retained its discretion, memorialized in the written agreement, on 

what to say at the sentencing hearing. R. vol. I, at 112. 

Ms. Welch suggests that the prosecutors effectively relinquished that 

discretion. This suggestion is invalid: relinquishment of discretion would 

have constituted a modification of the written plea agreement, which would 

have required a new, signed writing or a separate agreement with new 

consideration from Ms. Welch. As discussed above, Ms. Welch did not 

obtain a signed writing or provide new consideration for a new promise. As 

a result, the alleged oral statements did not create an enforceable 

obligation by “filling in” an open term. 

4. Our precedents on plea agreements are distinguishable. 

Ms. Welch mistakenly relies on our decisions in United States v. 

Brye, United States v. Hawley, and United States v. Mata-Vasquez. In Brye

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and Hawley, the government promised in a written plea agreement to not 

oppose a defendant’s requested sentencing term. United States v. Brye, 146 

F.3d 1207, 1212 (10th Cir. 1998); United States v. Hawley, 93 F.3d 682, 

691 (10th Cir. 1996). The plea agreement in Brye also included the 

government’s written promise to stipulate to a specified sentence. See 

Brye, 146 F.3d at 1210 (promising to stipulate to a sentence of “no more 

than [60] months”). In Mata-Vasquez, the parties agreed that an oral 

agreement was equivalent to a written plea agreement; but there, the 

parties had not signed a written agreement. United States v. Mata-Vasquez, 

111 F. App’x 986, 990 (10th Cir. 2004). 

These decisions do not apply here because Ms. Welch’s written plea 

agreement 

 did not limit the government’s discretion to take certain 

positions at sentencing and 

 specifically provided that additional terms were unenforceable 

unless made in writing and signed by all parties. 

* * * * 

In these circumstances, we decline to enforce the government’s 

alleged oral promises. They are unenforceable under the written plea 

agreement, lacked new consideration to constitute a new agreement, and 

did not relinquish the government’s discretion. 

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II. Even if an implied covenant of good faith and fair dealing existed, 

it was not violated. 

Ms. Welch also claims that the government breached the implied 

covenant of good faith and fair dealing. For the sake of argument, we can 

assume without deciding that this covenant exists in plea agreements. But 

even with this assumption, Ms. Welch’s claim would fail: the district court 

found that there was not “any evidence of bad faith” (R. vol. II, at 82), and 

we uphold that finding. 

Our review is limited, for we must decide only whether the district 

court’s factual finding entailed clear error. United States v. Williams, 292 

F.3d 681, 685 (10th Cir. 2002). To decide whether the district court 

committed clear error, we consider whether the court’s finding lacks record 

support or leaves us with a “definite and firm conviction” that the finding 

was incorrect. Id.

We apply this standard to the district court’s finding that “confusion 

between the parties resulted from the semantics used by each side,” not bad 

faith. R. vol. II, at 82. In making this finding, the district court 

characterized the government’s statements at the sentencing hearing as “so 

vague and lacking in substance that it carried no weight in the Court’s 

decision.” Id. at 82 n.1.1

 

1

 Ms. Welch argues that it does not matter whether the breach was 

intentional or affected the sentence. We decline to address these arguments 

because they do not affect our inquiry under the clear-error standard. 

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Ms. Welch disagrees, claiming that the prosecutor urged the district 

court to apply a 40-year sentence by stating that a 40-year sentence was 

“sufficient but not greater than necessary.” Appellant’s Opening Br. at 14, 

26; R. vol. I, at 310. For the sake of argument, we can assume that Ms. 

Welch is correct. But the prosecutor’s alleged support for a 40-year 

sentence would not require the district court to find bad faith. 

The government had already fulfilled its promises in the written plea 

agreement. At most, the prosecutor’s statement about a 40-year sentence 

might have conflicted with the alleged oral promises. But those alleged 

oral promises are unenforceable, and Ms. Welch did not rely on them. In 

these circumstances, we uphold the district court’s factual finding that the 

government had not acted in bad faith. 

III. Conclusion 

We affirm. 

 Entered for the Court 

 Robert E. Bacharach 

 Circuit Judge 

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