PIERRE TRUDEAU is Canada's prime minister--again. A resurrection, some call it. The Liberal who held the post for 11 years before his defeat last May to Joe Clark's Progressive Conservative Party has returned to claim the spoils of victory a mere nine months later. It is a remarkable personal triumph for Trudeau, who announced his resignation before the Tory government fell and who ran for prime minister only at the request of the Liberal caucus, which realized the impossibility of preparing for both a federal campaign and an intra-party leadership race. But Trudeau's triumph is ironic when viewed on a less superficial level.

The key to the Liberal campaign was a suppression of Trudeau's high profile. The Liberal leader has gone a long way toward dispelling the image of arrogance that cost him the spring elections, but the last thing Liberal strategists wanted to do was dredge up ghosts. Consequently, the Liberal campaign focused on Clark's flip-flops and his incompetence as a leader. They did not offer Trudeau as an attractive alternative; instead they tried to imply, by emphasizing Clark's failures, that any government would be preferable to a Conservative government.

This strategy stands in stark contrast to the last time the Liberals gained a majority. In the summer of 1974, clinging to a tenuous minority, the Liberals pushed Trudeau into the spotlight, presenting leadership as the crucial issue. He seemed unequivocally the best leader, and the Canadian electorate vested its support in him, rejecting the competent but drab alternative, Conservative Robert Stanfield.

By 1979, however, Canadians wanted to show Trudeau they resented his arrogance. Conservative strategists accordingly kept the youthful and fumbling Clark in the shadows of his own campaign. As Clark quietly canvassed the country, cloaked in the greatest degree of anonymity a potential Western national leader can be afforded, the Conservatives flooded the airwaves with anti-Trudeau messages. The strategy worked; 11 years of Trudeau were enough for Canadians. Only the Liberals' longstanding support in Quebec prevented a Tory majority.

But last week, Canadians--specifically voters in the linchpin province of Ontario--decided that nine months of Joe Clark was enough. They came to that conclusion despite clamor that the Conservatives had not been given a chance to govern, and despite a Tory advertising campaign that attempted to blame the country's problems on the 11-year Trudeau administration.

Clark could not back up his accusations of Trudeau's poor management with positive measures of his own. Interest rates climbed. His promised tax reductions were shelved. Perhaps most important, Ontarians had a sense that shone through in pre-election polls that with Clark as prime minister, no one would defend the national interest. This federalist sentiment, together with a belief in the need for strong central government, has always been strongest in Ontario.

Clark gave the impression of dismantling the federal authority. He talked of Canada as a "community of communities"; he said offshore resources belonged to the provinces; he tried to dismember Canada's national oil company, PetroCan, and repeatedly waxed inconsistent. In addition, he ceded Loto Canada, formerly the Olympic lottery, to the provinces, and most significantly, said he would not participate in Quebec's forthcoming referendum debate on secession.

On top of those actions came the austerity budget, reinforcing Ontarians' doubts about Clark's willingness to show concern for the province that unquestionably gave him his mandate. Why Clark so easily let Ontario slip away is beyond comprehension--perhaps he could not reconcile the West's pressures with Ontario's needs.

The Conservative strategy this winter corresponded to their strategy of last spring, a fatal mistake. The voters in Ontario, presented with a budget imbalanced in favor of Western Canada--Clark's electoral backbone--turned sour on the Tories. Even Ontario's Conservative premier, William Davis, criticized the austerity budget as unfair. The traditionally divided Tories thus repeated history by flailing at their own flag, leaving Clark with a tattered Tory rag.

The election results underscored Canada's regional voting preferences. The Liberals prevailed in all but one seat in Quebec, but failed to win a single seat west of Manitoba. When Trudeau composes his cabinet, he will face a problem parallel to one Clark faced: equitable regional representation. Whereas Clark had to struggle to find legitimate Quebec cabinet ministers, Trudeau will have to search for Westerners. Already there is a growing fear in the resource-rich West of political isolation; and there are rumblings of separation.

Despite Trudeau's overwhelming popularity in Quebec, Quebec's secession movement remains, spearheaded by Rene Levesque's Parti Quebecois. One disenchanted Canadian student watching the election returns Monday predicted, "Trudeau will be prime minister when Canada falls apart."

SO THE IRONIES begin to emerge. The Liberals used the same campaign strategy this election as the Conservatives did last spring, with similarly successful results. Trudeau's role as Liberal leader has come full circle: from being trumpeted as a powerful leader, to being hidden for fear of his arrogant image. The Conservatives gained their minority last spring on the strength of the vote in Ontario, with solid support in the West; this time, they foundered and finally sank in Ontario because their budget was perceived as inequitable, Clark's leadership as inadequate.

And there is an inkling that a "honeymoon period" does not necessarily exist in Canada. Although the voters did spare themselves another campaign by choosing a majority, they certainly did not resolve the fundamental conflicts that cast a specter over Canadian politics. Perhaps Trudeau will have to define what Canadians want before he can govern effectively. Given the country's cultural diversity and regional disparities, his task appears difficult.