This Article examines growing congressional interest in a specific legislative check on judicial power: controlling the types of cases judges are empowered to decide by expanding and/or contracting federal subject matter jurisdiction. Congress has recently sought to shape judicial power through a range of proposals that variously enlarge and compress federal subject matter jurisdiction. In 2004, for example, the House of Representatives voted to strip federal courts of jurisdiction over constitutional challenges to the Defense of Marriage Act and the Pledge of the Allegiance. Just a few months later, the new 109th Congress undertook a groundbreaking expansion of federal subject matter jurisdiction when it expressly empowered federal courts ...