Nick Confessore explains the Republican strategy for winning the swing states in this post from Tapped:

"First, the GOP, using what appear to qualify as illegal methods, has attempted to mislead thousands of Democratic-leaning voters in Nevada, New Mexico, Ohio, Pennsylvania, and elsewhere, into thinking they'd be registered but are not. (And Ed Gillespie, whose own outfit is funding these efforts via Sproul & Associates and God knows what other firms and consultants, is alleging Democratic fraud in precisely those states! Black is white. Up is down.) Consequently, those thousands of people are going to show up at polls and probably run into a lot of confusion and paperwork and problems. At the same time, Republican secretaries of state and election officials in Ohio, Florida, and elsewhere are pushing interpretations of election statutes that further muddy the waters for those who do get to vote.

Having done as much as possible to create the conditions for a confusing election, the GOP is getting ready to cast the inevitable results of that confusion -- people turning up in the wrong precincts, people who've moved from the neighborhood they originally registered and are trying to vote wherever they live now, and so forth -- as symptoms of outright election fraud. On Election Day, the GOP will challenge as many votes as they can at the polls, on whatever pretext is handy. They've already said they will. And then, if they're behind at the end of the day, GOP officials will start alleging massive voter fraud in Ohio, Florida, and elsewhere, whatever the facts on the ground are. That will give them a rhetorical advantage in the short-term -- if, say, John Kerry is far enough ahead that he declares victory, but there are still some votes to be counted or re-counted. And it's important for the long-term, too. If Kerry does win, but only narrowly, the GOP will allege that the Democrats stole the election, which will set the stage for later Republican efforts to shut down Kerry's ability to govern and deny him legitimacy."