Never mind the first Tuesday in November. Every day from now to Nov. 7 is Election Day somewhere in America.

People in Nebraska and Arizona, with some of the fastest starting gates, began early voting on the midterm elections this week. Absentee ballots have been cast in states including Iowa and Montana since last month. And around the country, polling places in different states will gradually be opening for business over the next month.

With more and more states allowing some form of early voting, it's a phenomenon that neither party can afford to ignore and that has transformed the traditional push to the polls from a 24-hour sprint into a month-plus marathon — sort of the political equivalent of the movie "Groundhog Day."

The stakes are huge: In all, 35 states comprising more than half the nation's voting-age population allow either unrestricted early voting or absentee balloting, according to HelpingAmericansVote.org, a nonpartisan commercial service that tries to encourage voting.

With a particularly emotional and polarizing election in the offing, early voting could help to boost turnout this year, although longer-term early voting trends have not found evidence of increased participation, said Curtis Gans, director of American University's Center for the Study of the American Electorate.

This year, just as in 2004, Gans predicted, "people will want to get their vote counted and not be subject to getting to the polls or to some of the problems at the polls that we saw in 2004 and 2000."

While Republicans traditionally have had the edge among early voters, Gans said, "in this election all bets are off as to who will show up in the early voting booths."

Both parties are working overtime to lock down early votes. Republicans are paying particular attention to early voters in states with hot races including Florida, Georgia, New Mexico and Arizona.

"It's an area where we are able to take advantage of our detail-oriented management style and highly effective get-out-the-vote operation," said Republican National Committee spokesman Danny Diaz. "It's an area where we expect to continue to achieve results and make gains on the opposition."

Democrats are in hot pursuit, actively financing early-voting programs in a number of states. In Iowa, for example, of the 92,000 absentee ballots that had been requested as of Wednesday, nearly 60,000 had been requested by Democrats, 19,000 by Republicans and the rest by people listing no party affiliation, according to the Secretary of State's office.

"If some of your targeted voters have already voted, then you can move on" to other potential supporters, said Stacie Paxton, a Democratic Party spokeswoman.

Early voting rules vary widely state to state. Oregon, for example, has conducted all its elections entirely by mail since 2000. This year, ballots will be distributed Oct. 20 and voters can mail them in, or drop them off at collection sites.

In Nebraska, where early voting started Monday, people can walk into local election offices to cast early ballots. In Douglas County, the state's largest, 144 people voted in person on Monday and Tuesday, higher than expected, according to County Election Commissioner Dave Phipps.

In Arizona, where early voting started Thursday, "it's no longer a one-day election, it's a 30-day election," said Mario E. Diaz, a political consultant who ran campaigns for Democratic Gov. Janet Napolitano in 1998 and 2002. Napolitano won by slim margins in both races, and Diaz credits early voting with making the difference.

In Iowa, where the process is known as no-excuse absentee balloting, people have been able to request ballots since Sept. 28. They can turn them in by mail or fill them out at county auditor's offices. In 2002, the last off-year election, a quarter of the state's ballots cast came in early, either by mail or in person.

Some of the leading states for early voting in 2004 were: Washington, where 69 percent of ballots were cast before Election Day; Nevada, 53 percent; New Mexico and Texas, 51 percent; Colorado, 48 percent; Tennessee, 47 percent; and Arizona, 41 percent, according to an AP compilation.

Elections officials say the early-voting trend is growing because of the convenience it offers to voters.

"People have busy schedules in this modern time, and the more dates that they have opportunities to vote, the better," said Meredith Imwalle, a spokeswoman for the National Association of Secretaries of State. "But it doesn't work for some states. Some states just sort of have a different election culture and it doesn't fit with their practices."

Paul DeGregorio, chairman of the federal Election Assistance Commission, says the jury is still out on whether early voting is a positive trend overall.

For one thing, "sometimes there is late information that comes out and then voters who have already voted may not have the opportunity to change their ballots," said DeGregorio. Furthermore, he said, there are added cost and security concerns when elections are stretched out over days or weeks.

On a more esoteric level, the "idea of people coming together in their communities to participate in democracy," complete with bake sales, American flags and chitchat at the polling place, can be lost when voters stick their ballots in the mail or drop them off early at a shopping mall, DeGregorio said.