WASHINGTON — President Bush and challenger John Kerry traded early victories Tuesday in a tense and testy contest between an embattled wartime incumbent and a hard-charging Democrat who blamed the Republican for chaos in Iraq and joblessness at home. With votes cast from Connecticut to Colorado, the race remained wide open.

The candidates sweated out a long night of vote counting and excruciating Electoral College math: It was too close to call in Ohio, Pennsylvania and Florida, with a combined 68 electoral votes, one-fourth of the coveted total of 270.

Among the other battlegrounds, Bush won West Virginia’s five electoral votes and Kerry battled back by winning the statewide vote in Maine, worth three electoral votes. Texas went for Bush and New York for Kerry, but these big prizes were no surprise.

There was suspense in the Senate, where Republicans held a 51-48 advantage with one Democratic-leaning independent. Democrat Barack Obama easily won in Illinois and will be the third black U.S. senator since Reconstruction.

Alongside the White House and congressional races, a full roster of propositions and local offices kept voters busy. But all eyes were focused on Kerry’s bid to make Bush the first president voted out of office in the midst of a war.

“I’ve given it my all,” the commander in chief said after voting at a Crawford, Texas, firehouse.

Kerry, a four-term Massachusetts senator, allowed himself to muse about the problems he might face in the White House, including a soaring deficit and a war that has claimed more than 1,100 lives.

“I’m not pretending to anybody that it’s a bed of roses,” the Democrat said.

The race showed signs of being as close as 2000, when Bush lost the popular vote to Democrat Al Gore but won the Electoral College count and the presidency after a ruling by the Supreme Court gave him Florida. The incumbent hoped to avoid the fate of his father — former President George H.W. Bush, who was bounced by voters in 1992 after waging war against Iraq and overseeing an ailing economy.

Voters were torn over the presidential race, in ways all too familiar.

Exit polls suggested that slightly more voters trusted Bush to handle terrorism than Kerry. A majority said the country was safer from terrorism than four years ago, and they overwhelmingly backed Bush.

Among those who said they were very worried about a terrorist strike, Kerry held a slight lead. That was a troubling sign for the incumbent as was this: A majority of voters said things were going poorly in Iraq, and they heavily favored Kerry.

With nearly 1 million jobs lost in Bush’s term, Kerry was favored by eight of 10 voters who listed the economy as a top issue.

The nation’s mood? There was division on that, too. Half said the country was headed in the right direction, a good sign for the incumbent.

Voters welcomed an end to the longest, most expensive presidential election on record. “It’s the only way to make the ads stop,” Amanda Karel, 25, said as she waited to vote at a banquet hall in Columbus, Ohio.

Bush won among white men, voters with family incomes above $100,000 and weekly churchgoers. Three-fourths of white voters who described themselves as born-again Christians or evangelicals supported Bush.

The president had hoped to increase his support among the religious right since 2000, but exit polls suggest there was little change.

Kerry retained Gore’s margins among blacks and union households, key parts of the Democratic base. His voters named the economy and Iraq as top issues.

One in 10 voters were casting ballots for the first time and fewer than 20 percent were young voters, hardly the groundswell that experts had predicted. Kerry was favored by both groups, according to the surveys conducted for The Associated Press by Edison Media Research and Mitofsky International.

Turnout could turn out to be the great decider. Spending more money than ever to target voters, Democrats enlisted a near army of paid organizers while Republicans issued marching orders by e-mail to legions of volunteers in the small towns and the farthest suburbs of battleground states.

Officials predicted a turnout of 117.5 million to 121 million people, the most ever and rivaling the 1960 election in the percentage of eligible voters going to the polls.

Legions of lawyers and election-rights activists watched for signs of voter fraud or disenfranchisement. New lawsuits sought clearer standards to evaluate provisional ballots in Ohio and a longer deadline to count absentee ballots in Florida.

Poring over exit polls and field reports, campaign strategists barked out 11th-hour orders to wrestle every vote from key states. At Bush’s headquarters in Arlington, Va., aides identified low-turnout precincts and dispatched more walkers to them. In Boston, advisers gave Kerry a longer-than-expected list of TV interviews to conduct by satellite to Wisconsin, Minnesota, Colorado, New Mexico, Nevada and Oregon.

That was an interesting list: Oregon was supposed to be safely Democratic and Colorado had seemed to be tilting toward Bush heading into Tuesday.

In the final hours of the campaign, Kerry’s aides tried to boost turnout in Hispanic areas by having the candidate’s wife, Teresa Heinz Kerry, do Spanish-language television interviews. Exit polls showed the Democrat winning the Hispanic vote, but not by as much as Gore in 2000.

Voters in Wisconsin, Michigan and Ohio received a wave of last-minute telephone calls as Kerry’s strategists sought to nail down victories in those key Midwest battlegrounds.

Bush won Mississippi, Louisiana, Alabama, Georgia, Indiana, Kentucky, Oklahoma, Tennessee, South Carolina, North Carolina, Kansas, Nebraska, North Dakota, South Dakota, Texas, Wyoming, Virginia and West Virginia for 170 electoral votes. One Nebraska electoral vote remained up for grabs.

Kerry won New York, Rhode Island, Delaware, Connecticut, the District of Columbia, Illinois, Maryland, Massachusetts, New Jersey, Vermont and statewide in Maine for 112 electoral votes. One Maine vote remained a tossup.

Democrats nurtured faint hopes of winning back the Senate. Republican Johnny Isakson took the seat held by retiring Democratic Sen. Zell Miller in Georgia.

Only nine of 34 Senate races on the ballot appeared competitive. One of them was held by Senate Minority Leader Tom Daschle, who was in a pitched fight against Republican John Thune.

All 435 House seats were up for election, but Democrats had little hope of a takeover. Republicans hold 227 seats, Democrats 205, with one Democratic-leaning independent and two vacancies in Republican-held seats.

With strategies molded by polls throughout the campaign, Kerry promised voters a new direction while Bush played up the risks of change.

Bush, 58, never more popular than the weeks after the terrorist strikes three years ago, constantly reminded voters of those days and cast himself as a strong, steady leader in an era of unease. He called Kerry indecisive and argued that Iraq was part of a global battle against terror.

“The people know where I stand,” he said Tuesday. “The people know I know how to lead.”

Kerry, 60, a decorated Vietnam War veteran, questioned Bush’s Sept. 11 response and often accused him of rushing into the “wrong war at the wrong time” in Iraq. He said the president refused to recognize problems at home and abroad, much less fix them.

Eleven gubernatorial contests were being decided Tuesday, along with 5,800 legislative seats in 44 states.

Among the notable ballot measures was one in California to devote $3 billion for stem cell research. Voters in Arkansas, Georgia, Kentucky, Michigan, Mississippi, Ohio and Oklahoma approved propositions that would ban gay marriage.