US: Candidates across America will today start nine weeks of intense campaigning for elections in November that could see Republicans lose control of Congress and open the way to a series of investigations into the conduct of the Bush administration.
Pollsters predict that Democrats will regain control of the House of Representatives and could even win a Senate majority in the biggest swing against a governing party since Newt Gingrich's Republicans stormed into Congress in 1994.
With Republicans demoralised by President George Bush's unpopularity and the military quagmire in Iraq, most polls give Democrats a double-digit lead as serious campaigning gets under way after today's Labor Day holiday.
"No one should expect the Democrats' popular vote advantage to be nearly that wide in November. It is safe to say, however, that Republicans are facing a motivation deficit that is unlike anything that they've seen since at least the 1982 midterm election, when unemployment hit 10 per cent just weeks before election day, and probably since the 1974 post-Watergate midterm election," said Charlie Cook, whose Cook Political Report poll gives Democrats an 11-point lead.
Democrats must gain 15 seats to win control of the House of Representatives, where all seats are contested every two years. Up to 40 House Republicans are vulnerable, including candidates in such conservative strongholds as vice-president Dick Cheney's state of Wyoming.
Only a third of the Senate's 100 seats are up for election and Democrats face a more difficult task in winning the six extra seats they need for a majority there. Democrats believe they have a good chance of winning Senate seats in Pennsylvania, Ohio, Rhode Island, Montana and Missouri and are targeting Republican strongholds in Tennessee, Arizona and Virginia but they are defending seats in Minnesota, Maryland, New Jersey and Washington against strong Republican challengers.
When Congress returns this week for a pre-election session lasting just 15 legislative days, Republican leaders will focus on national security, one of the few policy areas where they retain an edge over Democrats. Republicans hope to pass legislation giving congressional approval to Mr Bush's controversial domestic surveillance programme; to give a new legal basis to military trials for Guantánamo Bay inmates; and to improve security at US ports.
A resolution commemorating next week's fifth anniversary of the September 11th, 2001 attacks will give Republicans an opportunity to portray Democrats as weak on national security. For their part, Democrats will call for the full implementation of the 9/11 commission recommendations and will seek a vote of no confidence in defence secretary Donald Rumsfeld.
Republicans have yet to decide whether to make a last ditch effort to pass a compromise bill on immigration reform, an issue high on the list of voters' concerns. Immigration divides Republicans, with conservatives rejecting Mr Bush's call for a path to citizenship for millions of illegal immigrants in the US.
Despite the polls, Democrats are cautious about predicting victory in November, not least because Republicans, who have more campaign funds, have not yet started spending money in earnest. Republicans expect to spend $60 million between now and the election, about half of which will fund get-out-the-vote operations in key states.
Democrats are braced for an avalanche of negative advertising, with Republicans accusing their challengers of being unpatriotic and weak on terrorism.
Mr Rumsfeld signalled a more aggressive defence of the Iraq war last week when he compared its critics to those who ignored or appeased Hitler in the 1930s.
The Republicans' loss of the House or Senate would transform politics in Washington, opening the way for Democrats to launch congressional investigations into the Bush administration. Inquiries into how the case was made for the Iraq war and how the war has been conducted, with evidence broadcast on television every day, could be embarrassing for the administration, regardless of their outcome. Democrats could also inquire into the relationship between Mr Cheney and energy companies which helped to draft last year's energy bill, and also links between lobbyists and the Republican leadership.
Democrats have played down the prospect of seeking Mr Bush's impeachment, but November's elections could still herald a very uncomfortable final two years in office for the president.