Tony Blair and George Bush's love-in has collapsed over the rebuilding of Iraq. The two leaders have fallen out over plans for the reconstruction of the country and the heavy-handed action of American troops against the civilian population.

And the rift has been deepened by a Washington ban on a proposed morale-boosting visit by the PM to British troops in Iraq during the Christmas holiday.

... According to diplomats, relations between the allies have gone into "deep freeze" since the capture of Saddam Hussein last weekend.

President Bush was incensed that Mr Blair stole Washington's thunder by being the first Western leader to confirm that the former dictator had been arrested by US troops.

Downing Street rushed out Mr Blair's announcement before he had spoken to the American leader early last Sunday, when Mr Bush - six hours behind London - was still in bed.

Whitehall insiders confirmed that Mr Blair's decision was partly out of anger over a US veto on his proposed visit to British troops in Iraq during the Christmas holiday.

... Mr Blair and Mr Bush have had at least three phone conversations during the past seven days which Whitehall officials described as "increasingly terse".

A Downing Street insider said: "Relations between the two are at the lowest ebb since they first met.

"The PM is not happy at having to deal with Britain's European partners who have been left out of the rebuilding contracts. Of course they are still talking - but the diplomatic temperature is in the deep freeze."

I think there's a genuinely interesting dynamic at work here: Tony Blair supported the war on Iraq because he genuinely believed in it, but at the same time he also has an internationalist vision that is increasingly at odds with George Bush's.

... But in the end, Blair really is an internationalist. He wanted to get UN support, he was genuinely sorry that he couldn't convince Germany and France to get on board, and now that the war is over he truly wants to rebuild the old alliances. Bush, on the other hand, never really cared about that stuff and still doesn't. His instinct is to act alone.

Back in March I suggested that the Bush-Blair alliance wouldn't hold up forever, mainly because I didn't think that Bush would demonstrate any serious loyalty to Blair for the genuinely brave and risky stand that he took on the war. Blair is too canny a politician to ever publicly break with Bush, I think, but it wouldn't surprise me if their private relationship is getting increasingly testy. In the end, Bush doesn't really care about Blair except insofar as he supports what Bush wants, and there's only just so much of that that Blair can take.

What Blair is learning is that loyalty is a one-way street with George Bush: it's there as long as you support him unreservedly, but step out of line even for an instant and it's gone in a flash. As Fareed Zakaria put it just before the war, "should the guiding philosophy of the world's leading democracy really be the tough talk of a Chicago mobster? .... I can report that with the exception of Britain and Israel, every country the administration has dealt with feels humiliated by it."

Time and again, when I try to figure out what is happening in America, I keep coming back to the palpable sense of fear that seems to envelop us. We are seemingly afraid of everything: child molesters, terrorists, street crime, sharks - in a way that is wildly out of proportion to the actual danger they present.

... Our reaction to 9/11 has been the same. Instead of making use of the outpouring of support that we got in its aftermath, we have turned in on ourselves, and in the process we have changed from the flawed but generous nation that we are into a mean and paranoid country that lashes out at friends and enemies alike.

But we are not a cornered animal, and I hope that someday soon we will begin to peek out from our self-imposed isolation and realize it. The world is a dangerous place, yes, but it is far less dangerous when you face it with your friends at your side. We have many such friends in the world today, if we would only open our eyes long enough to see them.