Rupert Cornwell: You'd think it was the Thirties all over again

Chamberlain may have died, but listen to the speeches and he could be running in the US mid-terms

They are running against a desperately unpopular national leader, deemed responsible for dragging his country into a misconceived, unwinnable war. A strong feeling is abroad that the other party has been in power too long. More than a whiff of corruption is in the air.

No, I am not talking about David Cameron's Conservatives in this 10th year of Tony and his cronies, although it doubtless applies just as well. I have in mind the Democratic opposition on this other side of the Atlantic, in the seventh year of the reign of King George, two months before mid-term elections that may transform the US political landscape. For all practical purposes, the campaign starts today, Labor Day, the holiday that marks the end of summer and a return to life's serious business. Across the US, candidates traditionally attend rallies, barbecues and similar jollities in their states and districts, setting out their stall for the contest ahead. Defeat for the Republicans in the mid-terms does not, of course, mean the end for George W Bush - his countless admirers in America and around the world must wait until 20 January 2009 for that day of deliverance. But it would signify the beginning of the end. And for his party the prospects could scarcely be bleaker.

As James Carville, Bill Clinton's battle manager in 1992, recently put it, if the Democrats can't win either the House of Representatives or the Senate this time around, they should get out of politics. You can see his point. So low is Bush's popularity (37 per cent in one poll last week) that many threatened Republican candidates will not be seen with him.

But there is no escaping a President and his war, which a majority of Americans now believe was a terrible mistake. And when their minds are not on Iraq, Americans are worrying about their jobs and debts, as the long post-2001 recovery starts to falter and interest rates rise, and an outgoing economic tide exposes public deficits and personal indebtedness in harsh and equal measure.

Nor is the bar set that high for Democrats. In the House, their most likely capture, they need a net gain of just 15 among the 435 seats at stake. True, "redistricting" - as gerrymandering is politely termed here - has made it harder than ever to oust incumbents. Even so at least 20, and by some estimates up to 40, Republican-held seats are in serious jeopardy. In the Senate, the Democrats have a harder task. To regain a majority, they need a net gain of six in the 100-seat chamber. Five are pretty obvious but a sixth is distinctly problematic. A 50-50 split would leave Republicans in ultimate control, thanks to the tie-breaking vote of the Vice-President.

Nonetheless, today's climate of anger and dissatisfaction makes it perfectly possible that voters will hand control of the legislature in its entirety back to the Democrats for the first time in a dozen years. Indeed, the current atmosphere closely resembles that of 1994, the year of the last great earthquake in Congress. Led by the irrepressible Newt Gingrich, the insurgent Republicans then gained more than 50 seats and won back the House for the first time since the Eisenhower era. Now as then, with Congress's own approval rating at a pitiful 27 per cent, the mood is simply, "throw the bums out". If more of those bums are Republicans than Democrats, you don't need to be a Karl Rove to draw the obvious conclusion.

The Democrats, it should be said, have done little to deserve their good fortune. In 1994 Gingrich published Contract with America, a pithy 10-point manifesto that promised a return to probity, good governance and sound values. This time around the Democrats offer nothing similar. Instead, they are split on Iraq, unsure about economic policy, and divided on whether to return to a Clintonian strategy of centrism and compromise, or cast off into a more liberal yonder. Above all, they have failed to banish the sense that they are not quite to be trusted with the nation's security - and herein lies the Republicans' best, perhaps only, chance of success.

With the fifth anniversary of 9/11 a week away, the administration is already playing the card for all it's worth. The President evokes the 1930s, equating "Islamo-fascism" with Nazism. Iraq, we are told again and again, is the "central front in the war on terror". Donald Rumsfeld, the Defence Secretary, goes still further, equating Democrats who urge withdrawal from Iraq with the appeasers of the 1930s. Neville Chamberlain may have died in 1940. Listen to the speeches, however, and he could be running in the 2006 mid-terms.

But will these tactics work this time around? They did, brilliantly, for the mid-terms of 2002, when Bush exploited the recent memory of 9/11 to corral the Democrats behind his plan to attack Iraq. Two years later, they worked just enough to give the President his narrow re-election victory over John Kerry.

Now however, voters may not be buying it. Bush's ratings went up slightly after news of the thwarted London terror attacks (an operation for which the administration desperately sought to claim some credit). But they are now back where they were before. And barring an "October Surprise" - another 9/11 or the like - or a spate of good news from Iraq, they will probably stick there.

And in all of this, the Democrats are almost bystanders. "Had Enough?" could serve as their two-word Contract with America. Here, as in Britain, the old adage holds true. Oppositions don't win elections, governments lose them.