Specifically, he said he would make sure that Canada would be a full partner in the U.S. missile-defense program, which is still in the development stage.
On 22 February, Canada's new ambassador to Washington, Frank McKenna, restated that intention in Ottawa. But two days later, apparently hoping to save his fragile coalition government, Martin announced that Canada was opting out of the program.
On the surface, the rift appears to be over military matters. But analysts say the real issue has more to do with economics and trade.
Canada and the United States are the world's most active trading partners, worth an estimated $1.8 billion a day. They also have trade disputes, including one over U.S. lumber tariffs and an embargo on importing Canadian beef because of concern over mad-cow disease in Canadian livestock.
The missile-defense issue is merely the "economic annoyance that's reflected politically," in the words of John Hulsman, a foreign affairs analyst at the Heritage Foundation, a Washington public-policy research center.
"It's important to remember that [the United States and Canada] have the largest trading relationship in the world, and that means there's lots of possibility for friction. But these issues have dragged on. The other factor is Martin is in a minority government, dependent for his survival [on] the New Democrat folks, who are center-left and are really suspicious [of] any ties to America. That reality shows the state of the problem because being involved in missile defense can only help Canada. [Missile defense] can't hurt it."
Hulsman says that the 12-year-old North American Free Trade Agreement (NAFTA), which involves Canada, Mexico, and the United States, has been a great economic boon for all three countries. But he says, ironically, the increased trade has led to increased friction between the two countries.
"That constant irritation has made the economics, in a sense, better, but the irritants greater and the politics harder," Hulsman says. "So that paradox is where we are with the Canadians."
The trade friction goes deeper than that, according to Kent Weaver, who studies public-policy issues at the Brookings Institution, another Washington think tank. Weaver tells RFE/RL that the Bush administration has been wielding the huge U.S. economy as aggressively as it has used its military might.
He notes that in the lumber dispute, for example, the World Trade Organization (WTO) has found that Washington's tariffs break the organization's rules, and accuses the Bush administration of treating the issue lightly.
"The U.S. signed on to a set of rules [with the WTO and NAFTA] about how conflicts would be adjudicated," Weaver says. "And then when it doesn't suit the interests of U.S. domestic lumber producers, they say, 'Well, we're just not going to pay any attention to the rules and do whatever the heck we want.' [The Canadians'] concern is that NAFTA itself is threatened as a way of resolving conflicts and restraining U.S. exercise of pure power."
Weaver says Canadians generally have good relations with Americans but resent their bigger neighbor's trade practices: "[The United States is] a bully that's generally friendly. It's sort of like, you know, the big brother who you usually get along with, but, you know, is sometimes going to push you around."
On 23 March, Martin and Bush, along with Mexican President Vicente Fox, will meet at a summit, probably in Bush's home state of Texas. But neither Hulsman nor Weaver expects it to yield a significant improvement in U.S.-Canadian relations.