Bush would have won Florida by a margin of 10,000 - 15,000 votes, had the networks not prematurely declared victory for Gore in Florida before polls closed in the panhandle part of the state.
This projected margin of victory for Bush was confirmed even by Democratic activist/pollster Bob Beckel.
1. Were about to vote
2. Heard about the call
3. Believed it enough to decide not to vote at all.
When Jimmy Carter and the Dems made the same argument about why they lost some close California COngressional seats in 1980, we generally did not believe it, and careful research studies showed the same thing, to the extent that such studies can.
NOW, I will agree that in an election as close as Florida's, ANYTHING can make a difference. Just ONE vote per precinct in the Panhandle would have doubled Bush's margin. But, big numbers -- no way.
Also, since we easily, and correctly, dismiss all the Dem whining about people who were too stupid to punch the right place, or notice that they were double voting, etc., isn't it equally stupid for people to fail to vote (having waited to the last 10 minutes, BTW) because some network tells them so??