PEIRRE Elliott Trudeau is the dashing, elegant, liberal Prime Minister of Canada. He dates Barbra Streisand, wears wxhite carnations on his pin-striped lapels, and kisses girls as well as babies when he shows himself in public.

PR isn't his only side, of course. When Trudeau first ran for Prime Minister three years ago, he was regarded by many Canadians as something of an enfant terrible; brash, controversial, a dilettantish leftist who had even visited Communist China. But gradually, he oozed his way to the core of the political establishment, promising the nation that he would deal with Quebec's blossoming separatist movement in a way that would unify Canada, not rend it apart.

Finally, though, sheer virility won out. Two weeks ago, in a stunning tour de force, he drove the country into a state of martial law, stripping its people of all civil liberties and airlifting thousands of federal troops into the streets of Montreal. The object: to crush an underground separatist band known as Front de Liberation du Quebec.

How much farther was the Prime Minister prepared to go?

"You watch me," Trudeau snapped back at newsmen who cornered him on Ottawa's Parliament Hill. "There are a lot of bleeding hearts who don't like to see people with helmets and guns. All I can say is go on and bleed. But it is more important to keep law and order in the society than to be worried about weak-kneed people."

Indeed. And yet it appeared that the government had crumpled to its knees as well. The FLQ had kidnapped two of its men whom it was holding hostage: British Trade Commissioner James R. Cross and Quebec Labor Minister Pierre Laporte. In a sense, the imposition of military rule and massive search-and-arrest terror on the people of Quebec was the reaction of men who feared for their own safety and lives.

There was no other rational explanation for Trudeau's surprise move. The FLQ was known to be merely a tiny fringe of terrorists whose numbers probably did not exceed 150. Not only that: they were incapable of launching any sort of effective mass action by themselves because they worked through small, completely separate cells. The Liberation cell had kidnapped Cross, the Chernier cell was holding Laporte. There was every indication that the two groups had acted independently of each other, and there was no reason to believe that larger assaults would follow.

But then, one ought to give Trudeau some credit for being a competent political thinker as well as an out-and-out cad. The invocation of the War Measures Act, announced in the tense early morning hours of October 16, outlawed the FLQ and subjected its members to five-year prison terms. But it also placed in similar jeopardy anyone who "advocates or promotes the unlawful acts, aims, principles or policies" of the FLQ.

Interpreted narrowly, the law threatened all those who would "thus seek to destroy the basis of our democratic governmental system on which the enjoyment of our human rights and fundamental freedoms is founded"; the law's invocation would merely "insure the continued protection of those rights and freedoms in Canada." But buried beneath the platitudes was the distinct likelihood that Trudeau would use the crisis legislation to throw in jail those who posed the greatest legitimate threat to the government of his ruling Liberal party.

As police and militiamen swept through Quebec in a week-long blitz that involved 1600 raids and bagged more than 375 prisoners, it became clear that the government was carrying out a well-coordinated strategy of political terror. Very few of those arrested could be directly linked to the FLQ; most were a broad assortment of politicians, labor leaders and other public figures who sympathized with the underground terrorist group but did not endorse its activities.

WHAT TRUDEAU challenged, in effect, was a separatist movement in Quebec that had begun in the early '60's and was rapidly gaining strength and respectability in electoral circles as well as in terrorist cliques. One of the early groups, the Parti Quebecois, had attracted a significant province-wide following and won nearly 25 per cent of the popular vote in Quebec's elections last April. Another party, the two-year-old Front d'Action Politique, had been threatening to topple the administration of Montreal Mayor Jean Drapeau in the municipal elections last Sunday.

The FLQ itself was founded in 1960. Its movement had been a confused struggle that few people in Quebec really understood; it had begun with arson and bank robberies, progressed to bombings with the explosion at a strike-bound shoe factory in 1966, and escalated to the political kidnappings of earlier this month. The FLQ was always a self-consciously underground group, rarely offering any explanation of what it did, never attempting to build an above-ground political base. Its acts were characterized in the Canadian media as those of mad and reckless terrorists.

But there were a handful of men who identified themselves to the public as ideologues and spokesmen for the FLQ, and one of them, Pierre Vallieres, published an autobiography in 1967 which became the first comprehensive statement of the FLQ's methods and goals. Vallieres wrote Negres Blancs d'Amerique in the Manhattan House of Detention, where he spent four months after a protest in front of the United Nations building in New York. Quebec, since the establishment of the first trading post in Quebec by Champlain in 1608, has always been submitted to the interests of the ruling classes of the imperialist countries-first France, then England, and now the United States," Vallieres wrote in Negres Blancs. "It is by force and not by resignation, passivity and fear that we will be free."

It was at this time that the FLQ first became an overtly political entity with whom many French Canadians in Quebec could identify. And the need for some kind of political movement among French Canadians there had long existed. The French comprise 85 per cent of Quebec's population, yet they are the victims of severe economic and social discrimination: paid less, poorly housed, heavily unemployed. A provincial survey revealed last year that an English-speaking resident of Quebec earns roughly twice as much as one whose native tongue is French. In this context, the kidnapping of the Quebec Labor Minister was by no means an act of unmotivated terrorism; Laporte had long been called "Minister of Unemployment and Exploitation" by many French laborers in Quebec.

But even more striking is the fact that most capital investment in Quebec is owned, not by English Canadians, but by Americans. (Just before the invocation of the War Measures Act, Quebec Premier Robert Bourassa had returned from a whirlwind tour of the Wall St. investment community.) It was clear, the, that a nationalist struggle such as the FLQ's against the encroachment of Americans and English Canadians in Quebec would also be an economic movement to be waged along class lines. And the kidnapping of British Trade Commissioner Cross-who was abducted only after an attempt on the American commissioner had failed-was intended as an openly political act that might catalyze support for the FLQ.