BOOK REVIEW / POLITICS : Is the Great White North a Threat to the United States? : BREAKUP: The Coming End of Canada and the Stakes for America <i> by Lansing Lamont</i> ; Norton,$25, 256 pages

You know Lansing Lamont has his work cut out for him when you realize that the key point of this book--Canada could be a serious threat to the United States--is also the punch line in a comedy now being produced by director Michael Moore. In Moore’s Dr. Strangelovian film, a saber-rattling President gives a Niagara Falls sheriff (played by John Candy) the bright idea of invading Canada before it invades us.

Ha-ha, tee-hee: It’s hard to get worked up about this seemingly benign and innocuous “Nebraska North,” a place whose name, one legend goes, comes from Spanish fishermen off Newfoundland who remarked that there was aca nada , nothing here.

Perhaps our attitude derives from Canada’s historical role as a refuge from conflict, not a source of it. In 1776, 100,000 British loyalists found shelter on the shores of Canada’s St. Lawrence River. In the 19th Century, slaves headed True North on the Underground Railroad: “Farewell, old master,” went one hymn, “Don’t come after me / I’m on my way to Canada / Where colored men are free.” And in the 1960s, of course, anti-war protesters found sanctuary in a country where even the prime minister, Lester Pearson, had to suffer a dressing down by L.B.J. (After Pearson spoke out against the American bombing of North Vietnam in 1965, L.B.J. told him: “You pissed on mah rug!”)

Even Canada’s West, certainly wilder than our own topographically, was socially tame, populated not by robber barons, gunslingers and other American-style rogues but by the dutiful employees of the Hudson’s Bay Company.

In the ‘90s, however, Canadians have more than made up for their arguably prosaic past with a kind of political pandemonium that makes Ross Perot’s 1992 “challenge” to our two-party system pale by comparison. In last year’s elections alone, the nation’s long-dominant conservative Tory Party plunged from 157 parliamentary seats to two, while the leftist New Democrats retained only eight of their 44 seats.

Inciting most of the fervor is the growing desire of many French-speaking Quebecois to secede from Canada’s 127-year-old confederacy. In the scholarly but stylish “Breakup,” Lamont captures the depth of that desire by painting the scene at a Montreal disco palace Oct. 27, 1992, just after Canadian voters had rejected an accord aimed at thwarting secession:

As a burst of pyrotechnics engulfs the stage in flashing lights, smoke and whorls of sparklers, Quebec’s pro-secession leader, Jacques Parizeau, strides onto the stage. “Pounding steel drums mix with the cheering,” Lamont writes, “to create a pandemonium of sound atavistic, almost feral, in its intensity.”

Ten days from today, a similar burst of secessionist fervor is expected to boost Parizeau and his Parti Quebecois into power. If elected, Parizeau has promised to hold a referendum on Quebec’s secession within a year. While Lamont suggests that the Parti will win that referendum (it is only “a matter of time,” he writes, before Quebec secedes), recent polls show it garnering only 40% support.

In any case, the question remains: Is secession in Quebec’s, and Canada’s, best interests? Lamont’s answer is a resounding “no.” Strangely, though, his most persuasive arguments counsel just the opposite. Lamont points out, for example, that the reasons initially motivating Canada’s disparate peoples to unite--to ward off annexation by the United States and to affiliate with Britain, then the “mightiest empire since Rome”are no longer relevant.

By contrast, the arguments Lamont musters against secession are generally lame (Canada will lose its “enviable tradition of civility”) or alarmist (if Quebec secedes, he speculates, then who knows, maybe California or Texas will demand independence too!).

Fortunately, the jacket cover blurb helps explain Lamont’s fervent opposition to “breakup.” He is a former vice president and director of Canadian Affairs for the Americas Society, a U.S. think tank funded by such corporate interests as the Rockefeller Foundation. And no one is edgier about Canada’s dissolution than American business: Canada, after all, is by far our biggest and stablest trading partner, and pro-federalist interests such as the Royal Bank of Canada have been warning that Quebec’s secession could plunge the country’s living standard by 16% and send 1.2 million Canadians pouring into the United States.

The truth, of course, is that no one really knows the social or economic costs of Quebec’s secession. But in a bit of speculative fiction that Lamont uses to conclude his book, he sure makes them seem high. Taking us to a futuristic hydroelectric plant deep in Quebec’s subarctic forest, he follows an “assault force” of 300 Cree warriors, enraged by conflicts with the province that have been festering since 1990, when Quebec tried to build a golf course on an ancient Indian burial ground.

Descending a canyon-like staircase of huge terraces in the plant’s dam, the Crees attach hundreds of pounds of plastic explosive to its inner walls. When the charges are detonated later that night, the plant’s customers in Montreal, Quebec City and Boston are plunged into darkness.