Sometimes it seems as if all modern political history is simply a series of footnotes to George Orwell. Last month the Democrats swept to power in Washington, winning control of Congress for the first time in a decade. This, we were told, was a victory for the common man. After all those years of corrupt, fat-cat Republicans dispensing favours to their rich friends, at long last the worker, the unemployed, the dispossessed, were going to get a look-in. The animals would be taking over the farm from the humans.

But that was before Nancy Pelosi discovered the discreet charm of the private jet. It has been the custom since September 11, 2001 that the Speakers of the House of Representatives, for security reasons, get a private military aircraft to fly them to and from their constituencies. Ms Pelosi’s Republican predecessor, Dennis Hastert, an ample man with an ample entourage, made do with a small 16-seat commuter jet. But Ms Pelosi decided that was inadequate. She’d need something with a longer range to get her from Washington to her home in San Francisco.

But eyebrows were raised in the Pentagon when they saw what she had in mind. A US Air Force C32 would fit the bill nicely, she said; and it should have all the trimmings — 42 seats, all leather-upholstered, a state room, an entertainment centre, a state-of-the-art communications facility, a private bedroom and presumably, if Democratic pronouncements on climate change are to be taken at face value, enough carbon emissions to send a couple of small villages in SouthEast Asia sliding into the sea. Ladies and gentlemen, the seat belt sign has been turned off. You are now free to lord it over the country.

The Pentagon has denied Ms Pelosi her upgrade but the story is an instructive little parable about the power shift under way in Washington. Democrats are feeling pretty good about themselves right now. The Republicans, however, are in disarray, torn between the political exigency of repudiating their isolated President and the incalculable risk of splitting their party. Polls show their potential candidates for next year’s presidential election now losing to almost any Democrat. A gleeful but incredulous Democratic consultant said to me last week: “Surely even we can’t screw this one up?”

And yet these days of political abundance for Democrats carry with them a large burden. They know that it is Iraq, and George Bush’s failures there, that have presented them with their best opportunity in a couple of decades. But they know too that if they are really to succeed — not just win an election, but truly change the direction of the country — they must not only exploit the unpopularity of the war but come up with a foreign policy that genuinely replaces it.

American politics moves in a series of long cycles. For 40 years after the disastrous isolationism of the 1920s Americans trusted Democrats more than Republicans to handle their foreign policy. Roosevelt, Truman, Kennedy and Johnson all seemed more reliable leaders in a dangerous world than their Republican opponents. Only Eisenhower, the former general, managed to break the Democratic hegemony.

But the catastrophe of Vietnam, and the uneasy sense it produced that many Democrats were not really on America’s side, left a searing impression on the party and the nation. For the next 40 years, Democrats were considered unsafe. Only when domestic political issues — recession, stagflation, scandal — dominated debate have Democrats been able to win. But the mess in Iraq has the potential to change that.

Posturing — as the party did this week in the Senate, trying to pass nonbinding resolutions that condemn the war but offer no alternatives — will end up only reminding voters what they distrusted about Democrats. You can see the temptation, of course. Antiwar sentiment is now so strong in the country that all the Democrat contenders for the presidency are being pushed farther towards outright opposition. Hillary Clinton is busy modifying her previous modifications to position herself closer to the clearer antiwar stances of Barack Obama and John Edwards. On current trends, the three will soon be wearing bandanas, camping out in front of the White House, and openly considering signing Jane Fonda on to the ticket in 2008.

But there is a real opportunity for Democrats if they handle the next year or so correctly. Serious-minded foreign policy specialists in the party are trying to craft an approach that will not simply exploit antiwar sentiment but will align it behind a new strategic vision for the US. They say that Washington needs to relearn the lessons of the Cold War. The War on Terror will only be won, they say, in the same way — partly by military action when necessary, but even more so by victory in an ideological struggle. That requires demonstrating to the world, in this struggle for civilisation, that America’s way — what we used to think of as the West’s way — is the superior way, not simply by military means, but by winning the famous “battle for hearts and minds”.

These Democrats argue that the US is losing that struggle. And, glancing at the esteem in which America is held in the world, it is hard to dispute that. Of course that would matter less if America were not losing the military struggles, too — but it is. This is a view that resonates with many Americans, including Republicans, and could easily be a winning message.

The question is whether enough Democrats are willing to go down this difficult route of seeking engagement and compromise, or whether the instant satisfaction of indulging noisy antiwar sentiment will win out once again.

Times Recommends

• Exit Clinton. But what a show next!
• Angel of the South: the wrong horse
• Cannabis: who cares if it's B or C?