For many people, the question this year isn't just which presidential candidate to vote for, it's when.
States have done backflips to make it easier for people to vote in advance of election day. Presidential candidates are turning cartwheels to lock in early votes.
But in a campaign as volatile as this one, people have to decide whether it makes sense to vote too far ahead. The race is so unsettled that today's champ can be tomorrow's chump.
California, for example, is one of more than 20 states voting on Feb. 5. But people have been able to vote by mail since early January. That monthlong voting season is tantamount to a lifetime in this campaign.
Other Feb. 5 states where voting is under way include Arizona, Georgia, Illinois, New Jersey, New Mexico, Tennessee and Utah. Early voting in Florida, which holds its primary next Tuesday, began Jan. 14. As many as one-quarter of all ballots in the state typically are cast early.
In all, at least 32 states allow some form of no-excuse early voting, according to electionline.org.
Any vote that a candidate can secure early is precious, particularly when so many states are voting at once and campaigns are stretched thin. Many people like the convenience of voting early. But what about when the contest in both parties is so scrambled?
"The fluidity and uncertainty in the race would normally lead people to hold their ballots," said Paul Gronke, who directs the Early Voting Information Center at Reed College in Portland, Ore. "What is cutting in the other direction is that the campaigns are out there mobilizing people to vote early."
"They're getting hammered by these campaigns," Gronke said.
It isn't a coincidence that Democrats Barack Obama and Hillary Rodham Clinton are running their first California TV ads in the northern part of the state, which typically has the highest concentration of early voters.
Nor was it a coincidence that Rudy Giuliani, who is staking his campaign on a strong showing in Florida, was on a three-day bus tour across the state when Florida's early voting period began on Jan. 14. He did not miss the chance to lock up votes before his GOP rivals even arrived.
"I tell you what, before they even get here to campaign, how about you go vote for me?" he urged voters in New Smyrna Beach. "You can do something in Florida that you can't get done anywhere else. You can go vote today, you can go vote tomorrow."
It was music to his ears when someone in the crowd of 300 helpfully volunteered, "I already did! I voted for you!"
In Tennessee, one of the Feb. 5 states, about 14,300 people voted on Jan. 16, the first day of early voting, according to state elections coordinator Brook Thompson. That fits the usual pattern, in which voting typically begins slowly and picks up closer to election day, he said.
"In an election like this, where the fortunes of the candidates seem to be rising and falling daily, that tends to lead people to wait a little later," Thompson said.
Tennesseans, in particular, may have wanted to wait to see how homegrown candidate Fred Thompson did in South Carolina on Saturday. Some supporters suspected he might drop out if he did poorly. Sure enough, he finished a disappointing third in the first contest in his native South and quit the race Tuesday.
Some early voters in Michigan, where absentee balloting began Dec. 1 for a Jan. 15 primary, learned the perils of voting too far ahead.
Some people who wrote in the names of John Edwards or Obama later found out that their ballots were invalid when the two candidates declined to file statements allowing write-in votes. The state agreed to void the ballots and issue new ones to those who requested it. Five hundred voters requested new absentee ballots in Detroit alone.
Voters in New Mexico, where absentee voting is under way for the Feb. 5 caucus, showed how late developments can influence voting behavior. Requests for Democratic absentee ballots tripled to 600 to 700 a day after the state's governor, Bill Richardson, dropped out of the race, said Laura Sanchez, the state party's executive director. With their favorite son gone, New Mexico suddenly faced a competitive race, apparently driving up interest.
California is the biggest prize among the early-voting states. Stephen Weir, elections chief in Contra Costa County and head of the statewide registrars association, predicted that more than half the state's ballots will be cast by mail. But he said many early voters may hold off to see how the campaign develops.
"Some don't want to vote for somebody who might fall off the wagon," he said. "They want to wait to see who they think will be stronger against the opponent" in November.
Ace Smith, director of Clinton's California campaign, said it has spent months organizing for what amounts to "an election every day here for 29 days." The campaign has sent three mailings to voters judged most likely to vote early and vote Clinton.
Obama's campaign said it has placed 500,000 "neighbor to neighbor" calls trying to lock in early voters in California and Arizona. Absentee voters in Phoenix have gotten visits from Obama canvassers. In Obama's home state, Illinois, elected officials in Chicago helped to kick off early voting activities for the senator.
The Obama campaign said it also has pursued early voters in Tennessee, Utah and Georgia.
"All Obama supporters have been reminded about early voting and been given the tools to do so," said Obama spokesman Ben LaBolt.
Some candidates have not had the time or money to court early voters so aggressively.
Sen. John McCain, whose campaign was given up for dead before it came roaring back in New Hampshire, is looking for the Feb. 5 Super Tuesday contests to be "a momentum-driven day," said deputy campaign manager Christian Ferry.
For that momentum to kick in, though, McCain has to hope that people have not already voted for somebody else.