However, his power to pardon offenses against federal crimes is unlimited, which I think is perhaps the only such power in the Constitution. It’s never been dramatically abused, but the potential is there.
In a book I read recently, a wave of terrorism led Congress to pass a law giving jurisdiction over politically-inspired violence solely to the federal system.
The President promptly started pardoning anyone who killed one of his political enemies, giving him essentially the power to order executions at will. Entirely Constitutional, too.
On his last day in office in the last few hours (hopefully in January 2013), I expect him to get writer’s cramp pardoning anybody and everybody, as long as they come up with the dough to get that autograph................