Washington, D.C. (AP) – Congressional sources say President Barack Obama will nominate federal appeals court judge Merrick Garland to the Supreme Court.

Garland is the chief justice for the United States Court of Appeals for the District of Columbia Circuit, a court whose influence over federal policy and national security matters has made it a proving ground for potential Supreme Court justices.

A vacancy occurred on the nine-member court after the death of Justice Antonin Scalia.