President George W Bush has been making a final appeal for votes, in an attempt to boost support for the Republicans in the US mid-term elections.
Mr Bush said Republican principles were those of the majority
Speaking in Arkansas, Mr Bush said his party would win because it had the right policies on tax and security.
Democrats, whose lead has narrowed in final opinion polls, are focusing on Iraq, saying Republicans have blindly followed Mr Bush's "failed policy".
Democrats hope to win control of at least one of the Houses of Congress.
Both parties have sent thousands of volunteers to battleground states, but voter turnout is not expected to be above 40%.
Mr Bush, who also campaigned in Florida and Texas on Monday, said the Republicans would come from behind in the election.
"Our principles are the principles of the majority of the people in this country," he said at a rally in Arkansas.
"We're going to win this election because we're right on the big issues.
"You know I knew we were going to finish strong. I knew that we were going to come roaring into election day because we've got the right position on taxes and we've got the right position on what it takes to protect you from attack."
The BBC's Justin Webb in Washington says the president was making a late but vigorous effort to persuade Americans that continued Republican control of Congress is vital, and it does seem likely that the party will keep hold of the Senate at least.
But Democrats spoke of a change in mood up and down the country.
"People are starting to look around, and I have been to Tennessee and I have been to Missouri, and I've been to Rhode Island and I've been to New Jersey, I've been to Virginia, I've been to Maryland, and all across the country people are saying 'I think it's time for a change'," Illinois Senator Barack Obama said.
A third of the Senate, the whole House of Representatives and 36 governorships are up for election.
The Democrats need to pick up six seats to gain control of the Senate, and 15 House seats to have a majority there.
Mr Bush was snubbed by the Republican candidate for Florida governor, Charlie Crist, who missed the president's rally in Pensacola and held his own in Palm Beach, hundreds of miles away.
Correspondents say some Republican candidates are keeping their distance from Mr Bush, because of the president's low opinion poll ratings and the unpopularity of the Iraq war.
Mr Crist rejected Mr Bush in favour of former rival John McCain
Hundreds of thousands of voters have already cast their ballots, taking advantage of an early voting system.
Thirty-five states and the District of Columbia allow in-person voting before election day in certain cases - either at a voting machine or by absentee ballot.