"Sneering contempt" and "overweening power" are not impeachable offenses. Though I sympathize wholeheartedly with the author's sentiment, if we impeach Cheney, it should be for engineering and directing specific violations of the law. There are a number of examples.
As to the issue of his unprecedented role in this administration, well, the author actually unintentionally makes clear who must be held accountable for that:
"In contrast, Article II enumerates the powers and responsibilities of the president, including the obligation to take care that the laws be faithfully executed."
It W's responsibility ultimately to see that his administration behaves lawfully and appropriately. Everything Cheney has done has been with the President's explicit or tacit consent. If anyone should be held responsible for the breathtaking surrender of authority to vice presidency that we have seen, it should be the President who has failed to perform his elected duties. It seems silly to blame Cheney (much as you might dislike the man, and suspect that he runs intellectual circles around W) for accepting the authority delegated to him by the President. "The buck stops there," to adapt a phrase.
Of course, the issue is that a Presidential impeachment (or even vice-presidential) is pure fantasy. It won't happen. And if it did, guess who gets to be President? Seems like we're stuck for another 2 years.
Maybe we could dock their pay or something...