"History shows that the percentage of the vote that an incumbent president gets in the major polls before Election Day is an accurate predictor of the percentage of the vote the incumbent will win on Election Day. Thus, in Molyneux's judgment, the 'incumbent who fails to poll above 50 percent is in grave danger of losing his job.'...
The numbers of the challengers -- a list that includes third party candidate Ross Perot twice -- run better on Election Day than they do in the pre-election measures of public opinion. The average increase on Election Day in the actual vote for a challenger to a president is 4 percentage points."
That's the bottom line: this race is Kerry's to lose. Also, take the poll on the MLB playoffs!