"The president is in a good mood," White House spokesman Tony Snow said
before US television networks buzzed with predictions, based on partial tallies, that fed opposition Democrats' hopes of retaking the US Congress.
Bush, who hunkered down at the White House for a beef loin dinner with top advisers, snubbed television coverage in favor of getting minute-by-minute updates directly from officials running Republican campaigns, an aide said.
It was not clear whether those strategists were disputing early media predictions about the outcome, which was to shape his legacy and his last two years in office and could heap pressure on him to change course in Iraq.
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 judgment 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 midterm 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.
Bush planned to stay out of sight and break his silence on the hard-fought vote only on Wednesday, but aides insisted he was not worried about pollster predictions that the Democrats could retake the House of Representatives and
make gains in the Senate.
Bush "is monitoring the returns from the Residence with key staff members. They are getting the bulk of their information from field reports from people directly involved with the campaigns," said Bush spokeswoman Dana Perino.
US television networks showed that Democrats drew first blood, ousting incumbents in the Republican stronghold state of Indiana, and in Pennsylvania and Ohio, which was widely seen as deciding the 2004 presidential race.
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 of the 50 state governorships were on the ballot.