Both sides tend to say they trust the Gallup poll over all the others. Gallup has a historic measure not matched by most other polls. It is not always the most accurate, but based on its history, it is usually a great indicator of the trend.
Matthew Dowd has said that the person ahead in the Gallup poll after Labor Day would be the winner. There wasn’t much dispute from the Kerry folks, who assumed Kerry would be ahead. Kerry was not ahead, but Bush took a dive after the debates, which Gallup and every other polling company and media outlet showed were beneficial to Kerry.
The mainstream media might want to rethink how helpful the debates were for Kerry. Despite everyone saying he won the debates, Gallup shows Bush up 8 at 52 to 44 among likely voters.
The sample used by Gallup consisted entirely of people surveyed after the conclusion of the third debate. Watch for the Democrats to go extremely negative now.
Update [2004-10-17 14:24:48 by Erick]: With the WaPo/ABC Poll coming out today at 50-46-2 in favor of Bush, the RealClearPolitics average should go up to 4%, which gets Bush close to where he was before the debates.