They stand patiently in wilting heat for as long as three hours. Occasionally, the busiest and the frailest peel off, but the vast majority persevere, sharing sunblock, bottled water and an unquenchable eagerness to vote -- the earlier the better.

An already intense and unpredictable Election 2004 has turned even more so in the homestretch.

Florida opened the polls two weeks early to make voting more accessible, and the pent-up passions, hopes and fears of this presidential election season found expression in lines of voters who could not wait another minute to cast their ballots. In the words of Stephanie Calloway-Monroe, 29, who waited almost two hours on Thursday to vote for Democrat John F. Kerry: "It feels like we've been here since Jesus left, but I'm not leaving!"

"What if there's a crisis on Tuesday?" asked Kelly Daniels, 39, an international trade exporter, explaining why she waited 11/2 hours this week to vote for President Bush. "Anything can happen -- violence, whatever. It's so crazy. Now, no matter what, I've voted."

There were salespeople who said they had road trips on Tuesday, military personnel who said they had to report for duty -- and Marion Billups, 65, who took the fatalistic approach: "I don't even know if I'll be here on Election Day. Accidents happen."

Underlying the explanations was an intensity about the value of each ballot in a state that swung the 2000 election to Bush by 537 votes, amid allegations that thousands of votes went uncounted.

"I was out of town for the 2000 election and I voted absentee, and I believe I was one of those who lost our right to vote because our ballots weren't counted," said Elizabeth Shelton, who found a three-hour line at one voting site Thursday and drove 10 miles to find one with only a 11/2-hour wait. "Hopefully, if I put the vote in myself, my vote is safe."

In one of a package of reforms enacted since the deadlocked 2000 election, Florida became one of 23 states to open polls before Election Day, and -- as in the 22 others -- the response has astounded officials, politicians and analysts.

More than 1.5 million Floridians have voted early or absentee, according to analyses of voting data, and officials here predict that at least 20 percent of all those registered will vote before the polls open Tuesday. Other early-voting states report the same trend, including Arizona, Colorado, Iowa, New Mexico and Washington -- all of which, like Florida, are battlegrounds.

According to the University of Pennsylvania's National Annenberg Election Survey, 14 percent of voters had cast absentee ballots or voted by Wednesday, and an additional 11 percent said they would vote before Tuesday. In 2000, 13 percent voted before Election Day.

"This is really helping us," said New Mexico Secretary of State Rebecca Vigil-Giron (D), predicting that the surge of early voting will relieve at least some Election Day pressure on poll workers. "I was in Las Cruces a few days ago and the line was 200 deep to vote early, but people were okay with that because they knew if they didn't get to the head of the line by 7 p.m., they could always come back tomorrow to make sure their vote counted."

At early voting sites across Hillsborough County, which includes Tampa and is considered a battleground within this battleground state, there were almost as many reasons for the early-voting surge as there were voters. Laura Meares, a Kerry supporter and University of South Florida junior, has a paper due Wednesday and did not want to get stuck in line all day Tuesday. Calloway-Monroe, a customer service representative, has to work Tuesday and was afraid she would not have time to vote on her lunch hour.

An Air Force officer in uniform, who asked not to be identified, said he will be deployed before Tuesday to a location he cannot reveal and did not want to miss his chance to vote for Kerry. Joseph Jennings, 18, in line with his mother, Joy, 46, has to report for duty as a Marine on Tuesday in North Carolina, and wanted to make sure he got in his vote for Bush.

Black voters expressed much more concern about possible election fraud than did whites, particularly in Jacksonville, where 42 percent of 27,000 ballots thrown out in 2000 came from four heavily black precincts. Election officials in Duval County initially planned to open only one early voting site, far from the black precincts, but added four more after protests from civil rights and church groups and Democrats. Still, concerns were palpable.

"If they want something to go down, it's going to happen," said Tia Robinson, a black claims adjuster voting Friday in Jacksonville. On the positive side, she added, "It felt good drawing my circle around the name I voted for."

There are no statewide totals of early voters, and votes will not be counted until polls close on Election Day. But some counties have made numbers available, and Democrats appear to be considerably outstripping Republicans in turnout -- significantly, in the belt of counties across the state's midsection, from St. Petersburg to Orlando, the prime battleground for swing voters.

In Orange County, home to Orlando with a 5 percent Democratic edge in registration, 50,839 early votes had been cast by Friday morning -- 48 percent of them Democrats and 33 percent Republicans. In Pinellas County, home to St. Petersburg, where Republicans have a slight edge in registration, Democrats have a slight edge in early voters. In heavily Democratic Broward County, almost 130,000 votes were cast, with no party breakdown; and in Miami-Dade, almost 180,000.

Mindy Tucker Fletcher, a GOP strategist, said the Democratic advantage in early voters is irrelevant because Republicans have a bigger advantage in absentee ballots.

But Colleen Murphy, a Republican official in Orange County, posted an alarmist message on the party's Web site about the intensity and numbers of Democrats casting early ballots there.

"I want to tell you, it's been a culture shock," she wrote. "If you don't get yourselves out of your routines and your comfort zones and do what is necessary to support the president between now and November 2, I'm afraid we're all in for a little culture shock that will last beyond the next four years."

Matt Miller, Florida spokesman for the Kerry campaign, confirmed that early voting has been the chief priority of the Democratic campaign for the past several weeks. Independent "527" groups such as America Coming Together have been canvassing Democratic voters since the spring, and for weeks have urged them to cast early ballots for Kerry.

Knocking on doors in the upscale Pebble Creek neighborhood in northern Hillsborough County, two ACT canvassers found Wednesday that well over half their target audience had voted. One woman answered her door wearing an "I voted early" sticker, flashed a thumbs-up and said, simply, "Yes!"

Republicans began an intensive canvass Thursday night, with swarms of volunteers deployed to GOP precincts. Matt Strength, who chairs the University of South Florida's College Republican chapter, knocked on more than two dozen doors in a precinct that voted 68 percent for Bush in 2000 and where the GOP hopes to get 72 percent this year. Only four voters were home, and all promised to vote, but none had voted early. "I went three times and the lines were too long," one woman said.

Susan McManus, a political science professor at the University of South Florida, said one reason for the early voting is people's exhaustion from political ads, canvassing and visits from Bush, Kerry, their running mates, spouses, children and celebrity friends.

"They're worn down, and many of them just want to bring it to closure," she said.

Staff writers Darryl Fears in Jacksonville and Jo Becker in Washington contributed to this report.

Jesus Hernandez and Loretta Munoz examine a ballot at a Safeway in Denver. The wait has been more than two hours at some polling sites.In Tallahassee, the line of voters stretches outside the Leon County Courthouse, where students from nearby universities rallied participation.Registrar Susan Grisafi, left, explains the ballot to Elouise Carpenter in San Diego.Twenty-three states allow early voting, and interest has been high among Memphis residents.