British Prime Minister Tony Blair looked like the cat that had eaten the canary as he watched U.S. President George W. Bush heap praise on Britain as the truest friend the United States has ever had.

Mr. Bush's observation during a speech to Congress that Britain and the United States were once again joined in a great cause was a response to Mr. Blair's remark that the United States had helped Britain during the darkest days of the Second World War.

Score one for historical revisionism.

British-U.S. relations are, indeed, as solid as relations between the two leaders, and the United States did join the Allied cause -- after being attacked.

But the beginning of the modern era was not particularly auspicious.

"It is best and safest to count on nothing from the Americans except words," Neville Chamberlain wrote as war threatened.

But Winston Churchill, who succeeded Chamberlain as prime minister in May of 1940, was undaunted by the U.S. reluctance to wage war. Perhaps because he had an American mother, he heaped praise on Franklin Roosevelt with his enthusiasm for "these two great organizations of the English-speaking democracies."

The cosiness that Churchill wanted has ebbed and flowed during the past six decades, but it has been strong in recent years as the two imperial powers -- one long-faded, the other current -- seemed to find common ground.

In the 1980s, prime minister Margaret Thatcher found an ideological soulmate in president Ronald Reagan.

She stayed on the scene long enough to stiffen president George Bush's spine after Iraq's invasion of Kuwait in 1990, and her successor, John Major, was similarly enthusiastic about Operation Desert Storm.

Mr. Blair has continued in that tradition.

Some British commentators believe Mr. Blair carries the image of those wartime pictures of a grim-faced Churchill surveying the rubble of wartime London and that he yearns to follow suit.

Stephen Clarkson, a University of Toronto political scientist, has a simpler answer:

"I think it's straight good politics for him."

Prime Minister Jean Chrétien could only watch in Ottawa as the U.S. President failed to mention Canada in his speech Thursday night. If he wants solace for this exclusion, he need only consider that there were no U.S. officials on hand at the Washington train station in 1871, when Sir John A. Macdonald came to visit. Even worse, he had to wait two weeks for an audience with the man in the White House, Ulysses Grant.

Relations between U.S. and Canadian leaders have progressed reasonably well in the modern era, but there have been mismatches. Prime minister MacKenzie King and president Franklin Roosevelt got along, but president John Kennedy and prime minister John Diefenbaker were oil and water, while president Richard Nixon referred to prime minister Pierre Trudeau as "that asshole."

Prime minister Brian Mulroney got along famously with Mr. Reagan.

But the political hits he took after their 1985 singalong in Quebec City showed that Canadian prime ministers, unlike their British counterparts, cannot risk a too-cosy relationship with U.S. presidents.

"The trick for a Canadian prime minister is not to get too close and not too far from the United States, to reflect a grand Canadian ambivalence," said Lawrence Martin, author of The Presidents and the Prime Ministers.

"We like them, but we want to keep our distance and our independence." Of course, Mr. Bush may have had his own reasons for stiffing Canada. Britain brings an armed forces of with more than 500,000 personnel -- five times that which Canada can muster.