In a recent op-ed piece on Slate, Bruce Fein - the former Reagan Associate Deputy Attorney General - gets right to the point:
The House judiciary committee should commence an impeachment inquiry. As Alexander Hamilton advised in the Federalist Papers, an impeachable offense is a political crime against the nation. Cheney's multiple crimes against the Constitution clearly qualify.
Fein chronicles some of the high crimes and misdemeanors that demand impeachment, and says that the vice president could only assume the level of power he has attained when and if the president "is unable to discharge the powers and duties of his office", and publically transfers power to the vice-president, as described in the 25th Amendment to the Constitution. We all know that Bush has failed in discharging the powers and duties of his office, but he's never invoked the 25th Amendment to transfer power to Cheney. He just felt, from the beginning, that his Uncle Dick knew a lot a more than he did, so maybe he should be running the show.