Of even greater economic concern to Canada has been growing protectionist sentiment in the United States. Obama himself during the 2008 election campaign had attacked the North American Free Trade Agreement (NAFTA) as "a big mistake" and "devastating." Although he subsequently backed away from that sort of rhetoric, he has continued to criticize the outsourcing of American manufacturing to other countries. Canadians were particularly concerned about the "Buy American" provisions in his administration's massive economic stimulus package, which could potentially affect exports by Canadian manufacturers.

A related problem has been the "thickening" of the U.S.-Canadian border since September 11, 2001, as the United States tightened security, which has caused costly delays in cross-border trade and damaged Canada's tourism industry.

While a short visit could not resolve these serious issues, Obama and Canadian Prime Minister Stephen Harper seemed to find a lot of common ground.

Obama denied applying pressure to extend Canada's combat role in Afghanistan. "There has been extraordinary effort there and we just wanted to make sure that we were saying thank you," he said at a joint news conference with Harper. Indeed, both leaders have acknowledged that the solution to the conflict is not purely military, but requires a combination of military, development and diplomatic components. Once the Obama administration has developed its "comprehensive strategy," which is expected very soon, Canada may well be asked to play a role.

The two leaders also announced a "clean energy dialogue" that defused-at least temporarily-the "dirty oil" issue. The two countries will work together on developing clean energy sources such as biofuels as well as carbon storage technology. Harper also expressed his willingness to participate in a joint, continental approach to limit greenhouse gas emissions, quite an about-face for a leader who had denied the urgency of global warming and generally shown little interest in the environment.

Obama eased Canadian anxiety over trade by saying the United States would continue to abide by its commitments as a member of NAFTA and the World Trade Organization. Improvements in the environmental and worker-protection provisions of the NAFTA treaty could be done in a way "that is not disruptive to the extraordinarily important trade relationships" between the United States and Canada, he said reassuringly.

Harper used the press conference to make a direct appeal to Americans that Canada is every bit as serious about border security as the United States, and that the two countries should cooperate in a way that does not damage their economic relationship.

"Threats to the United States are threats to Canada," he said. "We as Canadians have every incentive to be as cooperative and alarmed about the threats that exist to the North American continent in the modern age as do the government and people of the United States. And that's the approach with which we treat the border."

Obama responded by stressing the need to ease bottlenecks and balance security concerns with an "open border."

"We have no doubt about Canada's commitment to security in the United States as well as Canada," he said.

The visit reassured Canadians that their country still enjoys a special relationship with the United States and that their interests won't be ignored as Obama grapples with the economic, strategic and environmental threats to the United States.

They were cheered by his parting words: "I love this country and think that we could not have a better friend and ally."

As for Harper, he continues to build his foreign policy around a tight relationship with Washington. He was ideologically close to Bush but now seems equally committed to working with the liberal Obama.

"He's an easy guy to like and an easy guy to get to know," Harper said in a post-visit interview with the Canadian Broadcasting Corporation.

More to the point, he admitted: "It doesn't matter who's right or wrong in a Canadian-American dispute-we lose."

Where Washington leads, expect Canada to follow.

The author is a member of the editorial board of the Toronto Star