O n October 2, 2017, the Supreme Court is to begin its new term. While the Court issued a number of notable decisions during its last full term, Court watchers have largely agreed that, at least compared to recent terms, the Court's October 2016 term was diminished both with regard to volume and content. The Court during the October 2016 term issued seventy written opinions and heard oral arguments in sixty-four cases, amounting to the lightest docket for the Court since at least the Civil War era. Unlike recent terms in which the Supreme Court issued major rulings on often-contentious issues like same-sex marriage, affirmative action, and abortion, legal commentators have noted that, in contrast, the October 2016 term did not include any cases that would tend to generate a comparable level of interest from the general public. The makeup of the Court appears to have directly affected the nature of the Court's most recently completed term. From the beginning of the term until April 2017, the Court was staffed by eight, rather than nine, Justices. As a result, the Court necessarily lacked an additional vote that could have allowed for additional cases to be granted for review or broken a tie in a relatively close case. And, in recent talks, Justices Samuel Alito and Elena Kagan both independently intimated that the eight-member Supreme Court actively worked during the past term to issue rulings in which the Court could find common ground to avoid 4-4 splits. The Court's efforts toward compromise and consensus during the October 2016 term may be evidenced in the number of unanimous rulings from the Court over the past year, with all of the Justices agreeing to the final judgment of the Court in 59% of the opinions issued during the October 2016 term. The open question is whether the Court—now with a full complement of Justices with Justice Neil Gorsuch's appointment in April 2017—will continue to find common ground at the same rate it did during the past term. With the Court already accepting over 30 cases, many of which raise difficult questions in various areas of law, the October 2017 has the potential to be one of the most consequential in years. For example, the Court has already agreed to hear: a major elections law case exploring the scope of a state's authority under the National Voter Registration Act of 1993 and the Help America Vote Act of 2002 to maintain voter rolls and remove inactive voters; a follow-up to a closely watched 2013 case exploring whether a foreign corporation can be sued under the Alien Tort Statute; a case on whether President Trump's March 6, 2017, executive order limiting certain foreign nationals and refugees from traveling to the United States violates the Establishment Clause of the First Amendment and exceeds the President's authority to restrict the entry of aliens; and a group of consolidated cases examining whether agreements to resolve employment-related disputes through individual arbitration, and waive class and collective proceedings, are enforceable under the Federal Arbitration Act and the National Labor Relations Act. A full discussion of these cases and others that the Supreme Court will hear during its upcoming term is beyond the scope of this report (indeed, the Court has to grant certiorari to the majority of cases that will likely make up its docket for the upcoming year). But Table 1 provides brief summaries of the cases the Court has already agreed to hear during the October 2017 term, and many of the cases on the Court's docket are discussed in existing or forthcoming CRS products. The majority of this report highlights four of the notable cases of the new term that could impact the work of Congress: (1)  Carpenter v. United States , which examines the limits the Fourth Amendment imposes on the warrantless collection of the historical cell phone location records of a criminal suspect; (2)  Christie v. National Collegiate Athletic Association (NCAA) , a case exploring whether Congress, by prohibiting a state from partially repealing a state law, impermissibly commandeers the powers of the state; (3)  Gill v. Whitford , which considers when a state's redistricting plan amounts to impermissible partisan gerrymandering; and (4) Masterpiece Cakeshop v. Colorado Civil Rights Commission , which asks whether a baker has a First Amendment right to decline to make cakes for same-sex weddings. Each case is addressed in a separate section below that (1) provides background information on the case; (2) summarizes the arguments that were or are likely to be presented to the Court in each case; and (3) examines the implications that the Court's ruling could have for Congress, including broader ramifications for the jurisprudence in a given area of law. Carpenter v. United States raises the question whether the government's collection of historical cell phone location data without a warrant violates the Fourth Amendment of the Constitution. The case could decide whether cell phone users have a protected Fourth Amendment privacy interest in the trove of location data held by their wireless carriers. The Fourth Amendment prohibits "unreasonable searches and seizures," which generally requires the government to obtain a warrant before conducting a "search." A "search" occurs if a government investigative measure violates a person's reasonable expectation of privacy. Thus, as the Supreme Court held in the landmark 1967 case, Katz v. United States , law enforcement officers contravene the Fourth Amendment if they attach a listening and recording device to a public telephone booth to listen to a suspect's conversations without a warrant. Importantly, however, the Supreme Court, under what is known as the third-party doctrine, has held that no reasonable expectation of privacy exists as to information that a person discloses voluntarily to third parties. Thus, the Court held in a 1976 case, United States v. Miller , that police do not violate the Fourth Amendment by obtaining microfilms of a suspect's account statements and deposit slips from his bank without a warrant because the suspect has voluntarily disclosed the information contained in those documents to the bank. Similarly, the Court determined in a 1979 case, Smith v. Maryland , that police do not violate the Fourth Amendment if, without a warrant, they ask a telephone company to install a "pen register" in its central office to record the phone numbers dialed from a suspect's home phone. The Court reasoned in Smith that because the suspect voluntarily conveys the numbers to the phone company when he dials them, he cannot reasonably expect such information to remain secret. Carpenter poses questions about how the third-party doctrine applies to more modern technology. The petitioner in Carpenter was convicted of a series of robberies. At trial, to tie him to the general location where the robberies took place, the government presented data about the towers to which his cell phone connected during calls made around the time of the robberies. Such data is known as cell site location information (CSLI). Instead of acquiring a warrant supported by probable cause, the government obtained Carpenter's CSLI from his wireless carrier under Section 2703(d) of the Stored Communications Act (SCA) of 1986. That provision allows the government to obtain a court order for wire or electronic communication records by offering "specific and articulable facts showing that there are reasonable grounds to believe" that the records "are relevant and material to an ongoing investigation." The probable cause needed for a warrant, in contrast, imposes a higher standard on the government. Carpenter moved to exclude the CSLI evidence on Fourth Amendment grounds, but the trial court denied the motion and the federal Court of Appeals for the Sixth Circuit (Sixth Circuit) affirmed. In Carpenter's case, the Sixth Circuit, relying on the third-party doctrine, held that the government's warrantless collection of the historical CSLI did not constitute a Fourth Amendment search. Just as a person does not have a protected privacy interest in dialed phone numbers, the circuit court reasoned, Carpenter did not have a protected interest in the location data that his phone transmitted to his carrier. The court framed the distinction as one between the "content of personal communications" and the "routing information" that transmission of those communications reveals: a reasonable expectation of privacy generally exists as to the first, but not the second type of information. The Sixth Circuit decision aligns with decisions of other federal appellate courts rejecting Fourth Amendment challenges to the warrantless collection of historical CSLI. But some judges on these courts, while accepting that the Supreme Court's third-party cases require this outcome, have nonetheless voiced doubts as to whether cases about phone booths, pen registers, and microfilm provide an adequate framework for analyzing privacy expectations in the smartphone era. One of the Sixth Circuit judges who decided Carpenter went even further. In a concurring opinion expressing disapproval of "the nature of the tests [courts] apply in this rapidly changing area of technology," the judge declined to apply the third-party cases. Instead, she declined to join the majority opinion holding that no Fourth Amendment search had occurred and, instead, voted to uphold Carpenter's convictions on an independent ground. Ultimately, only the Supreme Court can determine whether its third-party disclosure precedents should be retained, discarded, or modified to account for technological developments. The Court has considered Fourth Amendment cases about searches in the context of more modern technology in recent years, but it has largely avoided making major doctrinal pronouncements. In perhaps the most relevant case, United States v. Jones , the Court held that police violated the Fourth Amendment by attaching a Global Positioning System (GPS) tracking device to a suspect's vehicle to track his movements for 28 days. The majority opinion did not apply the "reasonable expectation of privacy" test. Instead, it made a much more limited holding under a theory of physical trespass: that a Fourth Amendment violation occurred when the police physically attached a GPS device to a vehicle without the suspect's consent. However, five Justices authored or joined concurring opinions concluding (in the case of four Justices) or expressing approval of the conclusion (in the case of the fifth concurring Justice) that the warrantless tracking violated the suspect's reasonable expectations of privacy.