Barack Obama has announced his nomination of Merrick Garland to fill the vacancy in the Supreme Court after the passing of Justice Scalia.
Garland is cuurently the Chief Justice on the District of Columbia Circuit Court of Appeals, where he has been on the bench since 1997. He was nominated to serve on the District of Columbia Circuit Court of Appeals by Bill Clinton at the end of his first term. Garland was not confirmed until after Bill Clinton won a second term and was able to push him through the Senate.
Garland is a fairly moderate judge. This nomination takes into consideration the dificulty of getting a more liberal judge confirmed by the Senate. Despite being considered moderate Garland still clerked under Brennan and was nominated to his current position by Bill Clinton.
He has decisions that may be considered liberal but are actually in favor of limiting Government power. In 2008, he ruled that suspects could not be held as enemy combatants without verifiable evidence. In 2013, he wrote the appeals court's decision ordering the CIA to release information about drone strikes to a federal judge, in a challenge brought by the American Civil Liberties Union.
The chances of Garlan being confirmed by the Senate are slim but it is not impossible given his credentials and somewhat moderate decisions on issues other than gun control while on the bench. Garlan was able to get confirmed by Republicans in the Senate when Bill Clinton nominated him to the Circuit Court.