You always learn what is really happening in Washington by going to parties and, in particular, to the right dinner parties. Though the F-15s and F-16s continue their surrealist, unending and unseen 24-hour-a-day patrols around 4,000 feet over the centres and symbols of power in DC, the parties are beginning to return to full throttle; but there is, naturally, still only one topic of conversation. People just in from New York say they can't take the smell any longer; Washingtonian insiders gossip on how Colin Powell is fighting a dove v hawk battle with Bush, Rumsfeld and Cheney in the White House (they've been getting the latest from the NS website, I suspect), and how the hapless chiefs of staff in the Pentagon simply can't yet come up with a battle plan that will satisfy the civilian hawks trying to get the show on the road.

Sotto voce wisdom that you will not read about elsewhere among Washington's cognoscenti: Bush is simply not up to it all, and Cheney is calling the shots. In the almost whispered words of a former very, very senior official in the Clinton administration: "Bush has been very, very uneven. But nobody can say that. I'm not saying that." There is unanimity, too, that the man most in charge of domestic security, the attorney general John Ashcroft - a far-right former Senator who was offered a job by Bush when he lost his Senate seat - is clearly rattled and has lost his bottle, terrifying the nation more and more, rather than giving it calm leadership. He must go as soon as it is decently possible, and Bush must lie low and let the grown-ups around him (Powell, Rumsfeld, and so on) get on with the job, they whisper. You will read little or none of this elsewhere, because the line is being spun frantically that Bush is supplying firm and tough leadership; several columnists around this land of free speech and expression have mildly questioned that assertion and then found themselves swiftly terminated, as Americans like to say.

Two of the friends with whom I was eating and drinking last Monday night now live in what used to be the US Embassy of Somalia, but is now an ultra-smart, multimillion- dollar family house. And that is emblematic, I think, of a lesson that is slowly seeping in here: that by giving foreign policy and foreign relations a lower and lower priority, especially since the collapse of the Soviet Union, the US is learning the price of its hubristic isolationism. What began as a humanitarian mission in Somalia in 1993 and ended as a Keystone Kops military commando mission that resulted in 18 American deaths, precipitated a total end of US interest in Somalia (and the Horn of Africa) that has now lasted nearly eight years. Likewise, the Clinton administration simplistically decided that Sudan was a bad country full of Islamic extremists, and so Sudan's offers to share with US intelligence its own intelligence on Osama Bin Laden simply slipped through the net until it was too late.

Had US intelligence been on its toes over such matters - and the CIA and its shortcomings were also very much a sotto voce subject of conversation last Monday, coming from people who knew what they were talking about - then, indeed, it is just possible that the terrible events of 11 September could have been averted. One close friend of "41" (George Bush I, the 41st president - as opposed to "43" in Bushiespeak) - told me that 41 agreed that the CIA (which he used to head) had been in disarray since the 1960s, when the Kennedy brothers sent it off to try to assassinate Castro. The Church Committee then investigated the nation's intelligence activities for 15 months before it was disestablished in 1976, but had in the meantime done much to lower the morale of US intelligence-gatherers, he said. "The CIA can't keep a secret," he added. "Our armed forces and government agencies are always fighting one other."

Bush - I'm back to referring to 43 now - spent the first six months of his presidency insulting most of the other nations of the world. He tore up the Kyoto Protocol, unilaterally abandoned the ABM treaty, told the rest of the world he wasn't interested in the proposed international ban on biological weapons, and so on. He was not into "nation-building", he said haughtily. The State Department watched as its buildings around the world decayed and became tattier by the minute, its officials too demoralised even to ask for more funds. (The one exception, because it was a story that impinged on most Americans via television, was when the pathetic, run-down old US embassy in Nairobi was bombed in 1998, probably by Osama Bin Laden's men, killing at least 141 Africans and 11 Americans; the replacement that has sprung up since consists of futuristic architecture costing $50m.) Thus Henry Cabot Lodge's "free hand" policy of eight decades ago took root and was suddenly alive and well with a carefree 43 in 2001.

The folly of all that struck home on 11 September.

Unchallengeable superpower it may be, but the attacks of that day showed America that it still desperately needs allies throughout the world, especially in those parts it has most neglected. In a land where toddlers are taught that sound investments bring dividends, the one area where the US had not invested adequately was in foreign affairs: as well as the long-standing refusal to pay its dues to the UN (something that has magically changed over the past month), US foreign policy spending and international aid programmes had taken a big dive.

The reason is something most Britons do not understand. I've said before that most of the American media have woefully little foreign news coverage - despite CNN's reputation, the number of people who actually watch it is tiny - and so the rest of the world has always been a distant, dangerous place to most Americans, where terrible things frequently happen. Britons might still see television pictures of starving babies in the third world, but Americans won't: ad time on prime-time television is too expensive to have room for it, and it turns off viewers. So there is little interest in foreign affairs - until, that is, Americans are affected, be it in Somalia in 1993, Kenya in 1998 or in New York City, the Pentagon and Pennsylvania in 2001.

The result of this insularity is that foreign policy decisions are often made for reasons purely of domestic politics - usually according to the interests of some lobby group or industry that happens to get the ear of a Congressman. Senators and Representatives have infinitely more power in making foreign policy than is the case in the UK, and a good proportion of them are abysmal bozos. "If I see someone come in that's got a diaper on his head and a fan belt wrapped around the diaper on his head, that guy needs to be pulled over," says one Republican Congressman, John Cooksey. You might assume this man is a safely ignorable Louisiana redneck, but he is actually an eye surgeon. Such people, many of them without passports or any real concept of the outside world, dictate routine US foreign policy far more potently than the president, his administration or the State Department. Motley groups of Congressmen have been able to dictate US policy towards Sudan, Cuba and Armenia - all in the interests of winning petty domestic policy goals.

Now we see an emergency, and this approach to US foreign policy is turned on its head. Those UN dues are paid. Millions of dollars of humanitarian aid have already gone to the refugees of Afghanistan. And with Colin Powell speaking to the leaders of no fewer than 80 other countries since 11 September, the US is perforce coming out of what was a self-defeating isolationism - cosying up, for example, to previously ignored little countries such as Kazakhstan. If humanitarian aid reaches people in the third world who need it, this will be one positive result from the terrible events here.

But the likes of the ultra-hawk Paul Wolfowitz, the man I revealed last week had been made deputy defence secretary by Cheney and Rumsfeld to "neutralise" Colin Powell, is determined that the enlightened Powellism we have been seeing will not go too far. "It's not one coalition [we're building]," he says. "It's different coalitions for different purposes." Er, quite. That is the kind of duplicitous doublethink that Powell faces in his quest to bring sanity to the war against terrorism.