I think ultimately the question being asked is not framed correctly. In point of fact, Bush doesn't have to do anything to "hang on to power", because there's one and only one available mechanism to remove him from office, and that's impeachment and conviction -- and that chances of that happening as long as the GOP controls the Congress is so close to zero that you couldn't see the gap with an electron microscope.

Even if, in a political miracle, the Dems retake the Congress in 2006, it's far from a slam-dunk that Bush or Cheney would be impeached, and, if impeached, convicted -- there are just too many conservative Democrats, too many folks with deep reservations about the damage done to the country by the (bogus) impeachment of Clinton, and too much chance that the GOP, however fractured it is by the events we're specualating about, will stick together and vote as a bloc. That adds up to a pretty low probability of anything happening.

So, absent impeachment and conviction, Bush stays in the White House, and as long as he's got the reigns of office there, he's got the power to do a lot of stuff by fiat and directive, without Congressional backing if necessary. We can only drive him out if he's got a conscience and is subject to feeling shame -- I've seen no particular indication that that is the case.