EVERY COUNTRY has its problematic national story: race in the United States, class in Britain, empire in Russia. Canada's problem is its perpetual identity crisis, a collective neurosis bred of being a confederation of English and French peoples--what the novelist Hugh MacLennan once called the country's "Two Solitudes"--and the small neighbor to one of history's few great nations. Canadians alternately worry about too much American attention--of being overwhelmed by the United States--and, as suggested by the title of a recent book, Invisible and Inaudible in Washington (2000), of being ignored by the United States. (It didn't help that the New Republic once judged the most boring headline ever to be "Worthwhile Canadian Initiative.")

These twin pressures have always existed as an immutable fact for Canadians and likely always will. But American policymakers need to be far more interested in how Canadians deal with these questions, since their answers will largely determine whether Canada is likely to remain a trusted ally in the unpredictable post-9/11 world or become a dangerously exposed northern flank.

The United States cannot "wall itself off" from Canada. Traffic across the 5,061-kilometer U.S.-Canadian border, which Ronald Reagan once hailed as "a meeting place between great and true friends", cements the most comprehensive bilateral trading relationship in history. A truck crosses the U.S.-Canadian border every 2.5 seconds. Approximately $1.3 billion in two-way trade crosses the border every day--or $500 billion a year. More than 200 million two-way border crossings occur yearly, making the shared border the busiest international boundary in the world.

Nearly 25 percent of American exports go north to Canada. More significantly, Canada is now America's largest source of crude oil and petroleum products. This may grow more important, both because of continuing instability in the Persian Gulf and because, according to the Oil and Gas Journal, Canada now contains, at 180 billion barrels, the world's second-largest proven reserves of oil. "Anyone watching what is happening up north will recognize that, before long, Canada will inevitably overtake Saudi Arabia as the world's oil giant", said Utah Senator Orrin Hatch recently. While chastising Canada for "irresponsible" talk of favoring China with increased oil exports as payback for the ongoing U.S.-Canadian softwood lumber dispute, Hatch nevertheless said that "we in this country don't want to be on Canada's shit list, ever."

Despite the senator's fears, however, Canada has much more to worry about than the United States. Quite simply, the border is Canada's economic lifeline. Owing to the absence of a large domestic market and an abundance of natural resources, Canada must export to survive. And today the United States consumes fully 85 percent of Canada's exports, accounting for an astounding 40 percent of the country's total GDP. In addition, many high-value Canadian products and services--for example, Canada's contribution to the U.S. space program--are designed to piggyback on existing American initiatives.

The signing of the U.S.-Canadian free trade agreement in 1988 (and NAFTA in 1993) accelerated the vertical integration of Canada's economy with that of the United States. Some 50 percent of Canadian foreign direct investment (FDI) is now aimed at the United States, while more than 60 percent of inbound FDI is American. According to Export Development Canada, a federal crown corporation, "the import content used to make Canadian exports has been growing steadily and now averages around 35 percent, and in many manufacturing industries [exceeds] 50 percent." This integration has, in turn, increased Canadian productivity. In short, it is no exaggeration to say that Canada's primary national interest is located south of the border.

The shock on Canadian economic activity of the effective closure of the border after 9/11 demonstrated the country's vulnerabilities and highlighted Canada's interest in safeguarding its southern frontier. The nightmare scenario for Canadian politicians today is a successful attack on the U.S. homeland by a terrorist who enters through Canada.

FACED WITH this reality, Canada has strengthened its anti-terrorism posture. Over the past four years, in addition to specific action on the border, the country's Parliament has passed Canada's first-ever Anti-Terrorism Act, a Public Safety Act and a new Immigration and Refugee Protection Act. Further, the government has created the Office of Public Safety and Emergency Preparedness, Canada's answer to the Department of Homeland Security, and has undertaken a foreign affairs and defense review. Canadian law now defines terrorism and designates terrorist groups operating in Canada. It is now an offense to support terrorist groups or any activities related to such groups. And security, intelligence and law enforcement agencies have been given enhanced powers of surveillance, arrest and detention, including preventive arrests or arrests without warrants.

Canada has established common procedures with the United States for the screening of high-risk goods in third countries prior to their arrival at North American airports and seaports, and the Department of Transportation has plans to increase the use of biometric systems and radiological scanners at Canadian points of entry.

Similarly, after 9/11, public pressure to rebuild the Canadian armed forces grew dramatically. In its 2005 budget, the federal government pledged an additional $11 billion to the armed forces over five years, a move supported even by the New Democrats, Canada's dovish social-democratic party. This marked the first substantial increase to the defense budget since cuts in the overall federal budget during the 1990s reduced military spending by some $25 billion.

And though Canada chose to sit out the Iraq War, Canadian special forces joined American units in Afghanistan in 2001 and later assumed the leadership of the International Security Assistance Force (ISAF) in Afghanistan. In the summer of 2005, the Canadian military enhanced its Afghan force and set up base in Kandahar. Using language Canadians had all but forgotten, Major General Andrew Leslie, former commander of Task Force Kabul and deputy commander of ISAF, predicted that Canada may be in Afghanistan for a generation: "There are things worth fighting for. There are things worth dying for. There are things worth killing for."

In sum, Canada has indeed acted to improve its overall security posture since 9/11. In keeping with the Canadian realist approach to bilateral continental relations, Canada has endeavored to safeguard its economic interests by satisfying American security concerns, which, according to former Canadian Ambassador Allan Gotlieb, "opens doors [in Washington] like no other key."

But if self-interest was clearly at work in Canada's post-9/11 security decisions, it is less clear whether the Canadian and American governments share the same global outlook. Whether Canada is a trusted ally of the United States--insofar as the latter has defined its global roles and responsibilities--is a more difficult question to answer. For in many disturbing ways, Canada seeks to unify its chronically fractured sense of nationhood in opposition to the United States.

BY AND large, Canadians like Americans. A recent comprehensive study of the country's attitudes reveals that 70 percent of Canadians "value and respect the United States and its citizens", while only 15 percent admit to not liking or respecting "anything that the United States and its people stand for." The problem is that, today, Canada's political reality reinforces the minority anti-American sentiment.

Traditionally, Canadians distinguished themselves from Americans on the basis of having a different political system. Canadians, said the great literary critic Northrop Frye, are Americans who rejected the revolution. However, over the last half-century, as centrifugal forces threatened to tear the country apart, opinion-makers began to distinguish Canadians from Americans on the basis of having a different value system.

Alarmed at the rise of nationalism in French Canada, and fearful that as the British Empire receded from memory the United States would replace Great Britain in the affections of English Canadians, a new breed of federal politicians and bureaucrats attempted to erase Canada's very real divisions (and centuries of history) by appealing to a largely rhetorical set of "Canadian values" shared by all from sea to sea. Only by appealing to these values, Canadian nationalists believed, would Canada overcome its cultural neurosis and emerge as a single, unified state capable of resisting the inevitable lure of the United States.

So, where Americans were religious, Canadians were now secular. Where Americans were a martial people, Canadians were now pacifists. Where Americans were conservative, Canadians were now liberal. Where Americans were greedy capitalists, Canadians were now empathetic social democrats. And these beliefs--reinforced by a large contingent of nationalist and anti-American media--rubbed off on the population at large. Today, Canadians consistently tell pollsters that they are more tolerant, more respected by others, better educated and friendlier than Americans. Oh, yes: and more modest, too.

This pattern shows up in international matters, as well. Canadians are confirmed multilateralists (except when they seize Spanish and Portuguese fishing trawlers on the high seas, bomb Kosovo without UN authorization, and unilaterally claim a 200-mile marine exclusive economic zone). Canadians are a "moral superpower" (except when it comes to official development assistance, where Canada's contribution ranks among the lowest of wealthy nations, despite the prime minister's pledge that "our foreign policy must always express the concerns of Canadians about the poor and underprivileged of the world"). Canadians are environmentally conscious (except that they consume more energy per capita than all OECD countries except tiny Iceland and Luxembourg and have no feasible plan for implementing their Kyoto promises). Canadians believe in international law and normative foreign policy (except when government agencies look the other way as their own citizens suspected of being terrorists are "rendered" to Syria or Egypt). And on and on it goes. "A country that seeks great changes and lacks the willingness to run great risks dooms itself to futility", the 17th-century English statesman Lord Clarendon is said to have remarked. He could well have been describing Canada today.