It's pretty clear that two of the document CBS aired were fraudulent. Assuming that CBS News retracts them on tonight's Evening News (and there are indications that Dan Rather will make and on-air apology), George Bush will win the election in November with an 8% to 12% popular vote margin and at least 100 vote margin in the Electoral College.
Why? The law of increasing returns, also known a piling on.
Momentum was already on Bush's side. That moment had been slowed only by the big media reopening his Air National Guard service with express intent of evening the score over the SwiftVets ads against Kerry. But the media went too far by creating fraudulent memos.
Some people will side with Bush out of sympathy for the foul play against him. Some will run away from Kerry assuming that the Kerry campaign must have had some hand in the felony. Many, many others will walk away in disgust, voting either for Nader or for no one.
Assuming Bush is now up 7 in popular vote and tied in the Electoral College, Kerry will likely drop 2% (Bush up 9) and Bush will gain 2% (Bush up 11%). This will come from those leaning toward Kerry and leaning toward Bush finally choosing hard. Those still truly undecided will decide not to decide. Polls after next week will change very little.