The new president must inject collaborative substance into the showy Three Amigos annual summits involving Canada, Mexico and the U.S. Until now, these meetings haven’t managed to disguise the fact that Canada and Mexico fix higher priority to their bilateral relationships with the U.S. than any of the three attach to their trilateral partnership.

Canadians suspect that skewed trade rules let them play—but not win—when Washington keeps score. Still, NAFTA is now far more popular in Canada, which has done well enough by freer trade, than in the U.S.—particularly in states losing manufacturing jobs to offshore competition. The challenge of balancing continental prosperity against U.S. jobs will test the new president when the discipline of power shades campaign promises into policy. It will also test the good will of Canada.

In his folksy way, former Prime Minister Jean Chretien captured the Canadian ambiguity towards the U.S. in a 1997 visit to Washington that is now remembered as the “Goldilocks Summit.” According to Chretien, U.S.-Canada relations were then as they should always be: not too cold, not too hot, but just right. For Canadians, just right is close enough to enjoy fluid access to U.S. consumers and close enough to shelter under its defense umbrella, but not so cozy that their country’s independence and culture are at risk.

Maintaining that balance has never been easy. It is even harder in a nervous new Millennium. After nurturing the myth that the 9/11 attacks were launched from Canada, the U.S. has settled on the notion that Canada can’t be fully trusted to keep Americans safe on their northern border. The persistent drumbeat across the 49th Parallel pounds out the warning: security trumps trade.

But for the relationship to move forward, the U.S.-Canadian border must be both impermeable to crime and porous to trade. Both countries must now move beyond the Smart Border agreement initiated by Canada after 9/11 to discuss ways of securing the North American perimeter with protocols and technology that separate specific risks from harmless traffic. These should be considered the first halting steps towards creating a customs union.

The region has much to gain from the success of such initiatives. Another former Prime Minister, Joe Clark, touched on the benefits spinning off the Canada-U.S. axis in a 2006 speech on Canadian foreign policy toward the Caribbean and Latin America. “When Canada’s relations with Washington are strong, other countries come to us, or listen to us, not just because of our own merits, but because we can influence the superpower.”

Carrying no heavy colonial or imperial baggage, Canada walks lightly in Latin America. To pick a self-evident example, Canada can do what the U.S. cannot in helping Cuba find its unique way forward—as long as Washington has learned the lessons Iraq teaches about self-determination.

There’s historical symmetry in the potential of a new U.S. Canada relationship. President George W. Bush, attending his first Summit of the Americas in Quebec City in 2001, held out the vision of a “fully democratic hemisphere, bound together by good will and free trade.” In 2009, the new president will attend his first Americas summit, this one in Trinidad and Tobago, and leaders will be wondering whether that vision is still meaningful. The hemisphere’s challenges, such as rebuilding the fractured consensus around the Free Trade Area of the Americas, all demand more attention and energy if the great expectations of past summits are to take specific shape.

Canada has a particular stake in these efforts. Prime Minister Stephen Harper, who has been criticized for pursuing a single-track foreign policy leading through Washington to Afghanistan, last year opened a second path to the Caribbean and the Americas. So far, its only notable accomplishment is a contentious trade pact with Colombia. But progress more in keeping with Canada’s internationalist credentials, particularly its ability to rebuild failed institutions, is as much in Washington’s interest as it is in Ottawa’s to make the region more prosperous, secure and democratic.

It’s not certain how far a fresh U.S. administration’s post-election attention span will stretch. Managing the so-called bad and good wars—Iraq and Afghanistan—will compete for time and energy with the economy and social challenges. Optimism and resilience, two long-time U.S. strengths, are weak. Congress—Washington’s other government—may not be as open to abrupt course adjustments as the President.

All of this argues that Canada, led by its Prime Minister, must seize the initiative. Instead of joining the give-me-this-and-that queue tugging at Uncle Sam’s sleeve, it can make life easier for the president by advancing an agenda serving the mutual interests of peace, prosperity and, of course, security. For a country traditionally wary of its powerful southern neighbor, this won’t be easy.

Still, this is the most promising moment in the relationship in nearly two decades. Canada sees in the change of administration a chance to resume speaking truth to a friend who is also an overwhelmingly powerful neighbor. Will Washington listen? Canada’s continuing commitment to Afghanistan, and its value as the largest, most secure source of U.S. energy and trade that make it the leading export market for 36 U.S. states, suggest that it should. Common sense and common interests also argue that the process should begin by quickly making routine and frequent the now sporadic meetings between the two leaders and their top advisors.

Canada and the U.S. now have a unique opportunity to boldly re-engage. Missing it would be a shame for the usually cautious Canada. But it would also be a shame for the new President, and for the Americas.