Voters across the United States headed to the polls on Tuesday with Democrats saying they plan to force a new direction for the Iraq war if they emerge from the midterm elections in control of Congress.

The Democrats believe they are poised to make major gains in both houses of Congress and plan to use any newly won power to rein in President George W. Bush.

President Bush and wife Laura after voting in Crawford, Texas, on Tuesday.
(CBC)

"We must reorder our national defence and foreign policy after this debacle in Iraq," Jim Webb, a Democrat running for the Senate in Virginia, said Monday.

"It's going great guns. We are way ahead of our targets everywhere," said New York Democratic Senator Charles Schumer on Monday.

"Every vote for a Democrat Tuesday is for a new, smarter Iraq policy." 

Voters will cast ballots for all 435 seats in the House of Representatives, for 33 Senate seats, for governorships in 36 states and for candidates in thousands of state legislatures and local bodies.

Americans will also make ballot decisions on such issues as gay marriage, embryonic stem cell research and minimum wages.

Republicans have controlled Congress since 1994. Pundits suggest the Democrats have a good chance of wresting control of the House from the GOP, but face a tougher challenge taking over the Senate. 

Amy Walter, an analyst with the Washington-based Cook Political Report, a non-partisan, online newsletter that analyzes U.S. electoral politics, said Monday the Democrats may not have enough momentum to take the Senate even though it seems to be the favoured political party of the day.

"I think four or five seats is a very reasonable prediction. Six seats, of course, is the majority. That could still happen. But I think right now we're probably looking at the lower end," she said.

The midterm elections are being widely seen as a referendum on Bush with two years left in office.

Bush was on the hustings on Monday night, shoring up last-minute support, but in a sign that he is seen as a liability even by some Republicans, Charlie Crist, who is running to replace outgoing Florida Gov. Jeb Bush, the president's brother, was a no-show at a rally in Pensacola, Fla.

"You're going to pick up the phone, you're going to make the phone calls, turn out your friends and neighbours and we're going to win," Bush told the crowd in Pensacola.

"I want to assure you, I see the danger. That is why we will stay in Iraq, fight in Iraq and win in Iraq."

Keying in on Bush's message of fear and danger, former president Bill Clinton, speaking at a rally for Webb in Alexandria, Va., mocked the Republican strategy.

"On the way to the poorhouse, you'll meet a terrorist on every street corner, and when you try to run away from that terrorist, you will trip over an illegal immigrant. You can't vote for them," Clinton joked.

The Republican incumbent in Virginia, George Allen, told his supporters that the vote will be tight and voter turnout is important.

"It's a close race. The world's controlled by those who show up. I've told all of you all here Mark Twain used to say thunder's impressive but it's lightning that does the work and it's these folks here who are the lightning," he said.

With files from the Associated Press