Everyone here has already written everything I'd of contributed otherwise, so won't try repeating these excellent points, this thread, other than to comment to that issue (Gore2000 voters and support turned instead and since to President Bush): 09/11 forced eyes open and minds to alert for many moderates who had become otherwise lulled into the liberal mantras that the Dems, with Gore especially, use to motivate voters (the "environment," the false 'righteousness' of being liberal, media as ruler and truth, glorification of socilism as solution rather than personal responsibility and production, and so much more).
I truly shudder at the thought of Al Gore in the White House during 09/11 and since, or at any time in the future. Unfortunately, for many moderates who were abhorred by Clinton, Gore appeared as a solution of "acceptability" (that I know him as not being, just saying, this is what I think was occuring in 1999/2000 that had some bordervoters leaning toward Gore, if not voting for him in 2000) while the reason to vote Republican at that time wasn't clearly identifiable for those new to politics, or voting with responsibility to issues beyond the "big tent" things of economy, healthcare, education.
Defense and national security were shown to be so needy after 09/11 that it opened the eyes for many, jolted them into examining closely how they voted and the consequences of for whom they did. A lot of voters, also, were not in touch with those consequences or if had been at one point, had accepted that their votes were meaningless...
That all changed when President Bush arrived and I am so grateful that he did and it did. Not for 09/11 but for the awakening of many Americans to responsibility of voting and as to the priorities to include our defense and military. The media had done a number on demeaning military capability for a long time prior to 09/11. And Bill Clinton also did his best to diminish our defense industry and military, even as to confidence. 09/11 whopped many people awake from the Clinton-esque sqandor of moral responsibility, I believe. Gore managed to squeak along on the "it wasn't me" rebuttal only so long before 09/11 made it clear as to his contributions to a failed America.