They already did the AIDS diagnosis plot line on
House...
I think if it went to your second scenario (President Bush attempting to remain in power) it would fail anyway from a complete breakdown in the government and legal system (Congress would impeach, he would have to try and arrest the Congress and a Supreme Court that no matter the accusations and beliefs of detractors wouldn't continue with any party line that goes that far).
As for the first, the question would have to be how you could know the legitimacy of what happens? And if it (being legitimate) causes people to switch their votes, then maybe they SHOULD be voting that way anyway if they are that worried, or just shouldn't be voting at all.
I think this IS paranoia, but I will say that there is no excuse or explanation short of military invasion of the mainland United States by a sovereign nation for a breach of the Constitution like is being proposed, and I know as someone who voted once (twice had I been old enough) for Bush and likely will for McCain that I wouldn't stand for it.