O n July 9, 2018, President Donald J. Trump announced the nomination of Judge Brett M. Kavanaugh of the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) to fill the vacancy on the Supreme Court of the United States caused by Justice Anthony M. Kennedy's retirement on July 31, 2018. Nominated by President George W. Bush to the D.C. Circuit, a court once described by President Franklin Roosevelt as "the second most important court in the country," Judge Kavanaugh has served on the bench for more than twelve years. In his role as a Circuit Judge, the nominee has authored roughly three hundred opinions (including majority opinions, concurrences, and dissents) and adjudicated numerous high-profile cases concerning, among other things, the status of wartime detainees held by the United States at Guantanamo Bay, Cuba; the constitutionality of the current structure of the Consumer Financial Protection Bureau (CFPB); the validity of rules issued by the Environmental Protection Agency (EPA) under the Clean Air Act; and the legality of the Federal Communications Commission's (FCC's) net neutrality rule. Since joining the D.C. Circuit, Judge Kavanaugh has also taught courses on the separation of powers, national security law, and constitutional interpretation at Harvard Law School, Yale Law School, and the Georgetown University Law Center. Prior to his appointment to the federal bench in 2006, Judge Kavanaugh served in the George W. Bush White House, first as an associate and then senior associate counsel, before becoming an assistant and staff secretary to the President. Before his service in the Bush Administration, the nominee worked in private practice at the law firm of Kirkland & Ellis, LLP for three years and served in the Office of the Independent Counsel and the Office of the Solicitor General. Judge Kavanaugh began his legal career with three federal clerkships—two for judges on the federal courts of appeals and one for the jurist he is nominated to succeed, Justice Kennedy. Judge Kavanaugh is a graduate of Yale College and Yale Law School. This report provides an overview of Judge Kavanaugh's jurisprudence and discusses how the Supreme Court might be affected if he were to succeed Justice Kennedy. In attempting to ascertain how Judge Kavanaugh could influence the High Court, however, it is important to note that, for various reasons, it is difficult to predict accurately a nominee's likely contributions to the Court based on his or her prior experience. A section of this report titled Predicting Nominees' Future Decisions on the Court provides a broad context and framework for evaluating how determinative a judge's prior record may be in predicting future votes on the Supreme Court. Because Judge Kavanaugh would succeed Justice Kennedy on the High Court, the report then focuses on those areas of law where Justice Kennedy can be seen to have influenced the Court's approach, or provided a fifth and deciding vote, with a view toward how the nominee might approach those same issues. Justice Kennedy's retirement is likely to have significant implications for the Court, Congress, and the nation as a whole. Justice Kennedy, often described as the Roberts Court's median vote, was frequently at the center of legal debates on the High Court, casting decisive votes on issues ranging from the powers of the federal government vis-à-vis the states, to separation-of-powers disputes, to key civil liberties issues. Accordingly, a critical question now before the Senate as it considers providing its advice and consent to the President's nomination to the High Court is how Judge Kavanaugh may view the many legal issues in which Justice Kennedy's vote was often determinative. As a result, the report begins by discussing two cross-cutting issues—the nominee's general judicial philosophy and his approach to statutory interpretation. It then addresses thirteen separate areas of law, arranged in alphabetical order, from "administrative law" to "takings." Within each section, the report reviews whether and how Judge Kavanaugh has addressed particular issues in the opinions he authored. In some instances, the report also identifies other votes in which he participated (e.g., votes to join majority opinions authored by other D.C. Circuit judges, votes on whether the D.C. Circuit should grant en banc review to a decision of a three-judge panel, etc.). The report also analyzes, where relevant, Judge Kavanaugh's non-judicial work, including a number of speeches and academic articles, many of which address the role of the judiciary, separation of powers, and constitutional and statutory interpretation. While this report discusses many of Judge Kavanaugh's non-judicial writings, it does not address two types of written work. First, the report does not discuss anything written by the nominee in a representative capacity for another party, such as a brief submitted on behalf of a client to a court, as such materials may provide limited insight into the advocate's personal views on the law. For purposes of this report, this limitation also extends to writings related to Judge Kavanaugh's former government service, such as his work for the George W. Bush Administration, the Office of the Independent Counsel, and the Office of the Solicitor General. Second, the report does not discuss the nominee's writings that predate his graduation from law school, as such writings may be of limited import to gauging his educated views on the law. While the report discusses numerous cases and votes involving Judge Kavanaugh, it focuses particularly on cases in which the sitting panel was divided, as these cases arguably best showcase how he might approach a legal controversy whose resolution is a matter of dispute and is not necessarily clearly addressed by prior case law. In addition, the report highlights areas where the nominee has expressed views on the law that may contrast with those of some of his colleagues. To the extent that the nominee's votes in particular cases arguably reflect broader trends and tendencies in his decisionmaking that he might bring to the High Court, the report highlights such trends. Nonetheless, this report does not attempt to catalog every matter in which Judge Kavanaugh has participated during his service on the D.C. Circuit. A separate report, CRS Report R45269, Judicial Opinions of Judge Brett M. Kavanaugh , coordinated by [author name scrubbed], lists and briefly describes each opinion authored by the nominee during his tenure on the federal bench. Other CRS products discuss various issues related to the vacancy on the Court. For an overview of available products, see CRS Legal Sidebar LSB10160, Supreme Court Nomination: CRS Products , by [author name scrubbed]. At least as a historical matter, attempting to predict how Supreme Court nominees may approach their work on the High Court is a task fraught with uncertainty. For example, Justice Felix Frankfurter, who had a reputation as a "progressive" legal scholar prior to his appointment to the Court in 1939, disappointed some early supporters by subsequently becoming a voice for judicial restraint and caution when the Court reviewed laws that restricted civil liberties during World War II and the early Cold War era. Similarly, Justice Harry Blackmun, who served on the Eighth Circuit for a little over a decade prior to his appointment to the Court in 1970, was originally considered by President Richard Nixon to be a "strict constructionist" in the sense that he viewed the judge's role as interpreting the law, rather than making new law. In the years that followed, however, Justice Blackmun authored the majority opinion in Roe v. Wade , which recognized a constitutional right to terminate a pregnancy. He was generally considered one of the more liberal voices on the Court when he retired in 1994. The difficulty in attempting to predict how a nominee will approach the job of being a Justice remains even when the nominee has had a lengthy federal judicial career prior to nomination. Federal judges on the courts of appeals are bound by Supreme Court and circuit precedent and, therefore, are not normally in a position to espouse freely their views on particular legal issues in the context of their judicial opinions. Moreover, unlike the Supreme Court, which enjoys "almost complete discretion" in selecting its cases, the federal courts of appeals are required to hear many cases as a matter of law. As a result, the courts of appeals consider "many routine cases in which the legal rules are uncontroverted." Because lower court judges are often bound by Supreme Court and circuit precedent, moreover, the vast majority of federal appellate opinions are unanimous. Perhaps indicative of the nature of federal appellate work, the vast majority of cases decided by three-judge panels of federal courts of appeals are decided without dissent. While the D.C. Circuit, where Judge Kavanaugh serves, witnesses more dissents on average than its sister circuits, the overwhelming majority of opinions issued by the nominee's court are unanimous. Accordingly, while Judge Kavanaugh's work on the D.C. Circuit may provide some insight into his general approach to particular legal issues, the bulk of the opinions that the nominee has authored or joined may not be particularly insightful with regard to his views on specific areas of law, or how he would approach these issues if he were a Supreme Court Justice. When a federal appellate judge takes the step to write separately, however, such an opinion need not accommodate the views of other colleagues, and can therefore provide unique insight into a circuit judge's judicial approach. Even in closely contested cases where concurring or dissenting opinions are filed, however, it still may be difficult to determine the preferences of the nominated judge if the nominee did not actually write an opinion in the case. The act of joining an opinion authored by another judge does not necessarily reflect full agreement with the underlying opinion. For example, in an effort to promote consensus on a court, some judges will decline to dissent unless the underlying issue is particularly contentious. As one commentator notes, "the fact that a judge joins in a majority opinion may not be taken as indicating complete agreement.