I am not to sure on who would have won. On one hand, Gore would use his experience on foreign policy as 8 years of VP, and Bush would have no foreign policy experience.
On the other had, Bush & the GOP would say "Look, you guys have had 8 years to launch the War on Terror and you didn't. This is the 3rd terrorist attack to happen on our soil under your watch! The WTC was already attacked once in 1993, then the Oklahoma City Bombing happened (although this was home grown terrorism), and now 9/11!"
That is a good point, that
four terrorists attack would have happened under the Clinton Administration. You forgot the bombing of the USS Cole. I don't think a fifth attack would look good for the Clinton Administration.
