As for this year, no one is sure. Both sides are paying unprecedented attention to turnout. The Bush campaign from the beginning has devoted far greater resources than previous Republican campaigns on voter registration and turnout operations. Bush spokesmen say they have attracted more than 1 million volunteers, with more than 50,000 in critical states like Florida, Ohio, Pennsylvania and Michigan. Democrats are also devoting more resources to registration and turnout than in previous years. They are relying on the labor unions, which have been their mainstay in the past, and also on liberally funded 527 organizations.
There is also a difference in motivation on the two sides. Democrats are motivated more by hate -- not too strong a word -- of George W. Bush than they are by positive feelings toward John Kerry, the candidate they settled on quickly to avoid the electoral disaster they thought they'd face if they nominated Howard Dean. Republicans are motivated more -- not by love, that is too strong a word -- but by affection for George W. Bush, and for the way he has stood up under the attacks of his opponents and the media.
That affection seems likely to be strengthened by Bush's performance at the second debate in St. Louis. Bush showed a sense of command and a command of facts and argument much greater than he had eight days before in Coral Gables, Fla. He seemed at ease and even cracked jokes.
John Kerry, on the other hand, often seemed on the defensive and fell into the habit of repeating himself that hurt Bush in their earlier encounter. His stentorian tones were unleavened by humor.
As this is written, no poll results have been announced, but my guess is that the balance of enthusiasm is likely to tilt toward Bush by about the same amount it tilted against him after the first debate. If that's right, Bush's numbers are likely to spike upward in the Gallup poll and to rise slightly in polls that weight for party identification.
But that may not be the final move. The balance of enthusiasm can change quickly, as we have already seen. And any significant change could change the outcome of this election.