President Barack Obama has chosen Merrick Garland, a 63-year-old judge on the US Court of Appeals for the DC Circuit, as his nominee to fill the late Antonin Scalia's seat on the Supreme Court, according to CNN, the Associated Press, NPR, and other sources. Republicans have promised to oppose any nominee, so action on the nomination before the presidential election in November is unlikely.

Garland has been near the top of Democratic shortlists for the Supreme Court ever since the Clinton administration. Obama seriously considered him in 2010 when John Paul Stevens retired, even giving him an interview; Elena Kagan eventually got that seat. Garland was also one of nine finalists to replace David Souter in 2009, when Sonia Sotomayor was nominated.

Unlike others on the Supreme Court shortlist, Garland won't make history. He's a white man, and so does not increase women or racial minorities' representation on the Court. He is, however, the oldest nominee in more than 40 years, since Lewis Powell in 1971.

Garland is the chief judge on the DC Circuit, having served there for nearly 20 years. DC's is by far the most prominent circuit court, owing to its jurisdiction over challenges to rules made by federal regulators like the Environmental Protection Agency, so Garland has been in a position of great influence for many years.

Before his appointment to the court, he spent much of his career as a prosecutor, serving as an assistant US attorney and as a senior official in Bill Clinton's Department of Justice, where he supervised both the Oklahoma City bombing and Unabomber cases.

Garland's 1997 confirmation was not unanimous — 76 to 23 — but he won broad Republican support. Current Sens. Susan Collins (R-ME), Orrin Hatch (R-UT), Dan Coats (R-IN), John McCain (R-AZ), and Pat Roberts (R-KS) all voted yes, and are still in the Senate. In 2010, Hatch, then the Senate Judiciary Committee ranking member, said there was "no question" Garland could be confirmed for a Supreme Court position.

Then again, Senate Majority Leader Mitch McConnell and Senate Judiciary Committee Chair Chuck Grassley both voted no on Garland in 1997, and they're the key senators whom Obama will likely need to win over if he has any hope of getting a nominee confirmed.

A mixed record on the DC Circuit

Garland has issued surprisingly few decisions on big, hot-button issues like abortion or LGBTQ rights.

DC v. Heller is perhaps the case for which Republicans have condemned him most strongly. That ultimately resulted in the Supreme Court striking down DC's handgun ban and establishing an individual right to bear arms in the Second Amendment. The Court was upholding a DC Circuit ruling by panel, which the court then declined to rehear as a whole (or en banc, in judicial parlance). But Garland dissented and wanted to rehear the case, suggesting he might have disagreed and thought the handgun ban was constitutional.

He also ruled in favor of a Clinton administration rule letting the federal government store gun-buyer records for six months. The right-wing judicial confirmation activist Carrie Severino has already attacked Garland for these positions in National Review. "He has a very liberal view of gun rights, since he apparently wanted to undo a key court victory protecting them," she writes. "He’s willing to uphold executive actions that violate the rights of gun owners."

Then again, Severino has offered measured praise of Garland in the past, saying in 2010, "Of those the president could nominate, we could do a lot worse than Merrick Garland. He's the best scenario we could hope for to bring the tension and the politics in the city down a notch for the summer."

Garland has a number of qualities that could make him more palatable to a Republican Senate than the average nominee. His age means his tenure is limited; they're not approving a John Paul Stevens who'll serve for 35 years.

Perhaps most importantly, his career as a prosecutor and his pro-police rulings reduce the odds that a liberal Court will overturn existing precedent on criminal justice issues, which is significant given that Ruth Bader Ginsburg and Stephen Breyer have both suggested they want to strike down the death penalty entirely.

"Judge Garland rarely votes in favor of criminal defendants' appeals of their convictions," veteran Supreme Court litigator and commentator Tom Goldstein has written. "Most striking, in ten criminal cases, Judge Garland has disagreed with his more-liberal colleagues; in each, he adopted the position that was more favorable to the government or declined to reach a question on which the majority of the court had adopted a position favorable to a defendant. Because disagreement among panel members on the DC Circuit is relatively rare, this substantial body of cases is noteworthy."

Garland even joined in a ruling that effectively barred Guantanamo detainees from seeking relief in US courts (a decision that the Supreme Court then reversed), though his defenders (including Goldstein) insist he was bound by precedent there.

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