O n March 16, 2016, President Obama nominated Judge Merrick Garland of the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) to fill the vacancy on the Supreme Court created by the unexpected death of Justice Antonin Scalia in February. Judge Garland was appointed to the D.C. Circuit by President Clinton in 1997, and is currently its chief judge, an administrative position that rotates among the active judges on the circuit. Prior to his appointment to the bench, Judge Garland served in the Criminal Division of the U.S. Department of Justice (DOJ), where he notably oversaw the prosecution of the 1995 Oklahoma City bombing case, as well as other cases. It remains to be seen whether or how the Senate might proceed in considering Judge Garland's nomination; however, his nomination generally remains effective until it is withdrawn or this term of Congress ends, whichever occurs first. This report provides an overview of Judge Garland's jurisprudence and discusses what the impact on the Supreme Court might be if he, or a judge of a similar judicial philosophy, were to be confirmed to succeed Justice Scalia. In attempting to ascertain how the Court's jurisprudence could be affected if Judge Garland were to fill the vacancy created by Justice Scalia's death, however, it is important to note at the outset that it is difficult to predict accurately an individual's service on the Court based on his prior experience for various reasons. Accordingly, a section of this report entitled " Predicting Nominees' Future Decisions on the Court " provides a broad context and framework for evaluating how determinative a lower court judge's prior record may be in predicting future votes on the Supreme Court. The report focuses on those areas of law where Justice Scalia can be seen to have influenced the High Court's approach to particular issues, or served as a fifth and deciding vote on the Court, with a view toward how Judge Garland might approach that same issue if he were to be confirmed. The report begins with his views on two cross-cutting issues—the role of the judiciary and statutory interpretation. It then addresses 14 separate areas of law, which are arranged in alphabetical order from "administrative law" to "takings." Within each of these sections, the report reviews whether and how Judge Garland has addressed particular issues in opinions he authored or joined, or in other votes in which he participated (e.g., votes regarding whether the D.C. Circuit should grant en banc review to decisions of three-judge circuit panels). The report analyzes majority, concurring, and dissenting opinions, as well as opinions of three-judge district court panels in which Judge Garland participated. Where relevant, the report also notes Judge Garland's writings prior to joining the D.C. Circuit, which often centered upon issues of administrative or antitrust law. The report discusses numerous cases and votes involving Judge Garland. However, it focuses particularly on cases in which Judge Garland participated that divided the D.C. Circuit, as these cases arguably best showcase how he might approach a legal controversy whose resolution is a matter of dispute and is not predetermined by prior case law. In addition, the report highlights areas where Judge Garland demonstrated views on the law that contrasted with the views of some of his colleagues. Moreover, to the extent that Judge Garland's votes in particular cases may reflect broader trends and tendencies in his decisionmaking that could be manifested if he were to be confirmed to the Court, the report highlights such trends. Nonetheless, this report does not attempt to catalog every matter in which Judge Garland participated during his 19 years of service on the D.C. Circuit. A separate report, CRS Report R44484, Majority, Concurring, and Dissenting Opinions Authored by Judge Merrick Garland , coordinated by [author name scrubbed], lists all opinions authored by Judge Garland during his tenure on the D.C. Circuit. Other CRS products discuss various issues related to the vacancy on the Court. For an overview of available products, see CRS Legal Sidebar WSLG1526, Vacancy on the Supreme Court: CRS Products , by [author name scrubbed] and [author name scrubbed]. It is important to note at the outset of this report that, at least as a historical matter, attempting to predict how particular Supreme Court nominees may approach their work on the High Court based on their previous experience 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 as he became a voice for judicial restraint and caution when the Court reviewed laws that restricted civil liberties and civil rights during World War II and the early Cold War era. Similarly, Justice Harry Blackmun, who had served on the U.S. Court of Appeals for 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 constitutionalizing the right to terminate a pregnancy in Roe v. Wade , and was generally considered one of the more liberal voices on the Court by the time of his retirement in 1994. The difficulty in attempting to predict future Supreme Court votes remains even when the nominee has had as lengthy a federal judicial career prior to nomination as Judge Garland. Federal appellate judges 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 and, as a result, tend to hear "many routine cases in which the legal rules are uncontroverted." 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. Unanimity is particularly frequent on the D.C. Circuit where Judge Garland serves. Accordingly, while Judge Garland's work on the D.C. Circuit may provide some insight into his general approach toward particular legal issues, the bulk of the opinions that Judge Garland 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. Even in closely contested cases where concurring or dissenting opinions are lodged, 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 may not necessarily reflect full agreement with the underlying opinion. For example, some judges, in an effort to promote consensus on a court, will refuse to dissent unless the underlying issue invokes particularly strong disagreement. As one commentator notes, "[T]he fact that a judge joins in a majority opinion may not be taken as indicating complete agreement. Rather, silent acquiescence may be understood to mean something more like 'I accept the outcome in this case, and I accept that the reasoning in the majority opinion reflects what a majority of my colleagues has agreed on.'" The caution with which one interprets a judge's vote isolated from a written opinion may be particularly important in the context of a judge's votes with respect to procedural matters. A judge's vote to grant an extension of time for a party to submit a filing, for example, generally does not signal any sort of agreement with the substantive legal position proffered by that party. Thus, while votes by Judge Garland in favor of having certain cases—which had been ruled on by three-judge panels—reconsidered by the D.C. Circuit sitting en banc have garnered considerable attention from some examining his judicial record, those votes should be interpreted with some degree of caution. On the one hand, a vote to rehear a case en banc could signal disagreement with the legal reasoning of the panel decision and may suggest that a judge wants the entire court to have an opportunity to correct a perceived error by the panel. On the other hand, as one federal appellate judge noted in dissenting from a decision to deny a petition for rehearing en banc, Most of us vote against most such petitions and suggestions even when we think the panel decision is mistaken. We do so because federal courts of appeals decide cases in three judge panels. En banc review is extraordinary, and is generally reserved for conflicting precedent within the circuit which makes application of the law by district courts unduly difficult, and egregious errors in important cases. As a consequence, a vote for or against rehearing a case, or on other procedural matters does not necessarily equate to an endorsement or repudiation of a particular legal position. Finally, it should be noted that, despite having served on the federal appellate bench for nearly two decades, Judge Garland has said very little about some areas of law because of the nature of the D.C. Circuit's docket, and as a consequence, it may be difficult to predict how he might rule on certain issues if he were elevated to the Supreme Court. Because of its location in the nation's capital and because of various jurisdictional statutes, the D.C. Circuit hears a significant number of cases on administrative and environmental law matters. In contrast, cases at the D.C. Circuit rarely, if ever, involve "hot-button" social issues such as abortion, affirmative action, or the death penalty.