By Lee Carter BBC correspondent in Toronto

Paul Martin and George Bush have differences to overcome

The president's visit comes at a time when he is deeply unpopular in Canada.

In a poll taken just before the US election, 85% of Canadians said they hoped Mr Bush would lose.

America's northern neighbour also opposed the US-led war in Iraq and has been adopting social policies that are at odds with the Republican administration in Washington.

Although Mr Bush visited Canada twice for summits during his first term, he has never made an official visit.

Washington stung

The president cancelled a planned visit in May 2003. Some observers concluded this was because of displeasure in Washington over Canada's decision, under then-prime minister Jean Chretien, not to support the US-led war in Iraq.

Since taking over the Liberal leadership at the end of last year, the new prime minister, Paul Martin has tried hard to repair the damage caused by his predecessor.

During Mr Bush's first term a senior Chretien aide referred to Mr Bush as "a moron" and a Liberal MP labelled Americans as "those bastards".

Canada's decision not to send troops to Iraq also stung Washington and led to a rare admonishment from the US ambassador to Ottawa.

Two-thirds of Americans believe you have to believe in God to be a good person, only one third of Canadians think that Michael Adams, author

It is a relationship that had become clearly strained.

Canada, used to being virtually ignored in the US, has recently become the new favourite target of right-wing radio talk shows and of the popular, notoriously outspoken Fox News TV network.

Typically, Canada is being depicted as a country that reaps all the benefits of living next to the US - including military protection - but is determined to bite the hand that feeds it with bouts of morally superior whingeing.

"Morons? Bastards? Maybe they don't want our business!" bellowed one Fox News commentator recently.

Locked together

By contrast, in the immediate aftermath of the US election, it was reported gleefully in the Canadian media that the country's official immigration website received six times as many visits than normal, from US citizens.

Meanwhile, satirical Canadian websites such as marryanamerican.ca urge Canadians to marry forlorn liberal Americans, to shorten their waiting time to immigrate to Canada.

Canadians like to believe that the Americans should be kept at a distance because there's a strong element in Canada that is always suspicious of American attitudes Professor John Ferris, military expert

The relationship between Canada and the United States is still a reasonably smooth-running operation. The two countries share the world's longest undefended border.

In recent years, both nations have locked themselves into a state of unprecedented interdependence. This is fuelled by the huge flow of goods created by the North American Free Trade Agreement (Nafta), and common defence and security concerns, heightened since the attacks of 11 September, 2001 on the US.

Despite the current cross-border disputes, its a trading relationship worth more than $200bn a year.

Canada remains America's largest trading partner.

But since the departure of former US President Bill Clinton from the White House in 2000, and his replacement by Mr Bush, a deepening gulf has emerged between Ottawa and Washington.

George Bush has his supporters in Canada

It is becoming more difficult for Prime Minister Paul Martin to diplomatically mask the social differences that position Canada so much at odds with US Republican values.

The most obvious of these is the virtual legalisation of gay marriage.

Court decisions in seven Canadian provinces and territories, have in effect legalised gay and lesbian marriages in more than 80% of the country.

Federal legislation is merely trying to catch up with what is already a reality.

Perhaps even more disliked by the US government and its drug enforcement agencies, is planned Canadian legislation to decriminalise marijuana.

"Martin is going to have a very difficult time balancing values that are more European, with interests that are more North American continental," says Michael Adams, the co-founder of Environics, one of Canada's leading market research companies and an author on Canadian-US relations.

Inextricably linked

Although the country's recent history has revealed a remarkable degree of divergence from what Canadians see going on south of their border, they know that they are inextricably and umbilically tied to their superpower neighbour, by geography, trade and defence.

"Canadians like to believe that the Americans should be kept at a distance because there's a strong element in Canada that is always suspicious of American attitudes," says Professor John Ferris, who teaches at the Centre for Military and Strategic Studies at the University of Calgary.