FOR FOUR DECADES the October Surprise has loomed large in the US electoral landscape. Every two years, in presidential and midterm congressional campaigns, as we approach the electoral witching hour of the first Tuesday in November, parties scan the horizon nervously for the unexpected event that suddenly shifts voters’ well-laid plans.

The original October Surprise was one that backfired. In 1968 President Lyndon Johnson hoped a late breakthrough in the Paris peace talks would end the Vietnam War just in time to produce a last-minute victory for his Vice-President, Hubert Humphrey, in the presidential election. But Richard Nixon persuaded the South Vietnamese Government to pull out of the negotiations days before the election; the talks collapsed and with them Mr Humphrey’s last hopes of a win.

Ever since, as the calendar runs down towards Hallowe’en in election years, agitation in both political parties increases sharply that the other one has something scary hidden. But like the ghosts and goblins that haunt suburban neighbourhoods at this time of year, these October scares generally exist only in the fevered minds of the politicians; terrors for children that, as November dawns, give way to the more easily recognisable realities of electoral politics.

It would certainly now take an October Surprise of truly supernatural dimensions to prevent next month what looks like being the largest convulsion in American politics in more than a decade. After 12 years in the wilderness after the Republican Revolution of 1994, the Democratic Party is poised to wrest back control of the House of Representatives. Polls suggest too that the Senate, which Republicans have controlled for all but one of the past 12 years, is much closer to falling than seemed possible only a month ago.

If one House goes, November 7 will confront President George Bush with a difficult domestic environment in his last two years in office and set the framework for a crucial presidential election two years later. If both go, it might well mark one of those periodic turning points in American politics.

Three factors are turning what once looked like a steady trickle of voter discontent into a tidal wave: the insistent attrition of incumbency; the war in Iraq; and disaffection among conservatives at what they see as a betrayal by their party’s leaders.

Time and its close ally, tedium, are the enemies of all incumbents. Even the famed power of American politicians to channel oodles of public money towards their constituents in what is widely called an incumbency protection racket cannot always overcome the simple power of “time for a change”.

Iraq is hastening the flood. The disaster that is the daily dose of news from the country is persuading undecided voters to send a signal of urgent rejection of Mr Bush’s foreign policy.

Meanwhile, conservatives are as miserable as they have been in years. The legislative record of Republicans in Washington — record high levels of public spending, an unedifying litany of financial and sexual scandals among party leaders, Mr Bush’s efforts to liberalise immigration laws radically — have sharply increased the inclination of many conservatives simply to stay at home next month.

The implications of this impending revolution for the US and the world are not yet clear. But the outlines of a tumultuous couple of years are hoving into view.

Democrats are in angry and buoyant mood. Out there in the salons of San Francisco and the shopfloors of Ohio, they want blood. Vengeful anti-Bush sentiment is as splenetic as it is on the Left Bank or the West Bank. The party’s leaders are eager to dismiss the idea that their control of the fearsome legislative and supervisory powers of Congress will turn the next two years into an orgy of Iraq war recrimination and investigation of the Bush White House.

But they are already geared up for inquiries into weapons of mass destruction claims, conduct of the war and the awarding of postwar contracts to well-connected American companies. Investigations have a way of creating their own momentum. Once the Pandora’s box of secrets is forced open by congressional subpoena, there’s no telling what will be left.

In policy terms, Democratic control will also have more far-reaching consequences than the party currently indicates. Democrats will not cut off funding for the war. But the political climate for maintaining the large US commitment will surely become intolerable. By the end of next year it will be astonishing if there are as many as half the current US troops in Iraq.

The same pressure will apply to other foreign policy fields. President Bush is under no constitutional constraint to get approval from Congress if he decides he needs to attack Iran’s nuclear facilities. But in his likely political predicament, beset by investigations, limping towards retirement, it is not hard to guess what might be the fallout if he did choose that route.

The longer-term implications of the impending November revolution are harder to predict: much will depend on how the two parties react. Already, the 2008 presidential race on the Republican side is dominated — most unusually — by potential candidates who are appealing to the centre ground. Senator John McCain, the former New York Mayor Rudolph Giuliani and Mitt Romney, the Governor of Massachusetts (a Republican from Massachusetts!), are likely beneficiaries if the shock of losing Congress gives Republicans real hints of their political mortality.

On the Democratic side it looks already like heavy sledding for the moderates. The main candidates are 2004’s presidential and vice-presidential nominees, John Kerry and John Edwards, and, perhaps, the former Vice-President Al Gore, all appealing to an angry and emboldened antiwar base that regards the long-time front-runner Hillary Clinton as way too centrist for their tastes.

Republicans rowing aggressively towards the centre while Democrats pull sharp left? There’s a real October (2008) surprise for you.

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