NEW YORK // Americans will vote today in congressional elections that will shape the rest of Barack Obama's presidential term and, in turn, determine whether the first black president of the United States is re-elected in two years.
Opinion polls showed the opposition Republican Party poised to win control of the House of Representatives and erode the Democratic Party's majority in the other chamber of US Congress, the Senate, leaving leaving Mr Obama unable to push through the kind of big legislative reforms that marked the first half of his presidency.
If Republicans control the House, they could follow through on their promise to try to repeal parts of the healthcare reform bill or stymie financial reform, while blocking movement on issues remaining on Mr Obama's agenda, including immigration reform, climate change and Middle East peace.
With less than 48 hours before Americans headed to the polls, Mr Obama went on a weekend campaign swing through several key states in an attempt to revive the kind of enthusiasm that swept him to power two years ago. That fervour has waned as voters grapple with a moribund economy and a 9.6 per cent unemployment rate.
"This election is a choice between the policies that got us into this mess and the policies that are leading us out of this mess," Mr Obama told a rally in Cleveland, Ohio on Sunday. "If everyone who fought for change in 2008 turns up to vote in 2010, we will win this election."
But the Republicans were in fighting form. Sarah Palin, the former Republican vice-presidential candidate and a key force behind the right-wing Tea Party movement, said voters would provoke a "political earthquake".
"They're going to say, 'You blew it, President Obama. We gave you the two years to fulfil your promise of making sure that our economy starts roaring back to life again'," she told Fox News Sunday. She is a paid contributor to the network.
Campaigning for the 2012 presidential elections will, in effect, get under way tomorrow in a radically different political landscape if the opinion polls prove correct in their predicted big swing to the Republicans. There will be fierce competition for the Republican presidential nomination among the dozen or so possible contenders to take on Mr Obama.
"The single most important thing we want to achieve is for President Obama to be a one-term president," said Mitch McConnell, the Senate Republican leader, last week.
Obama aides criticised Mr McConnell for promoting political gridlock. "There will be more Republicans. We are ready to work together. The question is, are they ready to work with us?" David Axelrod, White House senior adviser, told MSNBC.
Political pundits speculated whether Mr Obama would want to act like Bill Clinton, who after Republican gains in the 1994 congressional election moved to the centre and compromised with the strengthened opposition.
While the Republicans might want to block Mr Obama at every turn, they will also want to promote their presidential prospects in 2012 and an obstructionist agenda could prove damaging.
"If they want to stick with this filibuster strategy, obstruction and saying no, it's going to be difficult to do anything," Richard Durbin, the second-leading Democrat in the Senate, said on Sunday.
His boss and Senate majority leader, Harry Reid, was embroiled in one of the highest-profile races in Nevada where polls showed a slight lead for Sharron Angle, the Tea Party candidate. Her unorthodox views, such as once wanting to abolish the federal education department, have won her few friends in the Republican establishment but appeared to be resonating with voters worried about government spending and the budget deficit.
All 435 House seats, 37 of 100 Senate seats and 37 of 50 state governors' offices will be decided today. Republicans must win 39 Democratic seats to take power in the House and 10 to take the Senate. A Pew Research Center poll released on Sunday showed the Republicans taking the House with 48 per cent of support, compared to 42 per cent who favoured the Democrats.
Until the US economy turns around, analysts expected right-wingers to continue finding fertile ground in blaming minorities, such as immigrants. The inward-looking nature of US concerns was reflected in the current election cycle, which saw jobs and the economy dominating the debate with the wars in Iraq and Afghanistan barely registering.
