Recovering from a final campaign push that took him to 10 states over five days, Bush voted at the firehouse in his tiny adopted hometown of Crawford, Texas, then flew back to Washington to await the judgement of US voters.
The US president, dropping his fierce rhetorical attacks on opposition Democrats, issued a final rallying cry for voters to turn out for the crucial mid-term elections even as worry-faced aides predicted victory.
"We live in a free society, and our government is only as good as the willingness of our people to participate in it," Bush said as he stood with his wife Laura outside the firehouse, an "I voted" sticker on his shoulder.
"And therefore, no matter what your party affiliation, or if you don't have a party affiliation, do your duty; cast your ballot and let your voice be heard," he said.
The latest opinion polls stoked opposition Democrats' hopes to make strong gains in the legislative elections, largely due to widespread anger over the Bush administration's handling of the war in Iraq.
But some the polls showed evidence of a late surge of voter intentions in favour of the Republicans, who predicted that their fearsome voter turnout operation would erase the Democrats' advantage in the battle for control of the Senate, House of Representatives, and key state governorships.
For seasoned political experts, the day after the election also marked the official start of the battle to decide Bush's successor in November 2008 election.
Democrats needed to pick up six of the 33 Senate seats up for grabs to win that chamber and 15 seats to capture the House of Representatives, where all 435 spots were in play. Thirty-six state governorships were on the ballot.
But even before US voters cast their ballots, the White House was signalling that it would not change course on Iraq, regardless of who won the
election and of the fact public opinion polls show that the war is deeply unpopular.
"It may not be popular with the public. It doesn't matter, in the sense that we have to continue the mission and do what we think is right," Vice President Dick Cheney told ABC television on Sunday.
"We're not running for office, we're doing what we think is right," said Cheney.
At his final pre-election rally on Monday, Bush fell back on his well-worn political rhetoric, branding Democrats as tax-raisers who cannot be trusted to wage the global war on terrorism he declared after the September 11, 2001 attacks.
Recycling a message that served him well in the midterm 2002 elections and the White House race two years later, Bush told armies of Republican faithful that "we're at war" with terrorists and said Democrats have "no plan" to win.
"Harsh criticism is not a plan for victory. Second-guessing is not a strategy," he told thousands of supporters here. "We have a plan. Stick with us and the country will be better off."
The White House hoped to have contained the political danger from anger over Iraq by painting the Democrats as defeatists who had no idea how to win, and seizing on Saddam Hussein's death sentence as a sign of progress.
Democrats hoped to punish Bush and fracture his Republican Party's monopoly on power after a gruelling campaign soured by vicious mudslinging over the war and general public unhappiness with politics.
The result will also hinge on how much issues such as skyrocketing health care costs, stem-cell research, gay marriage, abortion, the economy and illegal immigration weigh on voters' minds.

Copyright AFP (Agence France-Presse), 2006