Ottawa — The Conservative and Liberal suitors for Canada's next election look remarkably alike. So it is not entirely surprising they are courting supporters in each other's camp.
The Progressive Conservatives' new leader, Brian Mulroney, has come onto the Canadian political scene as a breath of fresh air in the same way that Pierre Trudeau, leader of Canada's ruling Liberals, breezed onto the scene 15 years ago.
''Brian Mulroney,'' says veteran Canadian political commentator Peter C. Newman, ''has set in motion the changing of Canada's political guard . . . he is the very best man the Tories could have chosen, and he will make a great prime minister.''
And many Canadians think he will become Canada's next prime minister, replacing Pierre Trudeau. Mr. Newman adds that a Mulroney victory would ''eventually . . . improve the tone of public life in Canada,'' something that many Canadians say Mr. Trudeau did 15 years ago.
There can be no doubt that Mr. Trudeau launched a veritable political revolution when he came to power in 1968, taking a firm hold on governmental machinery almost immediately and dominating Canada and Canadian affairs in ways unfamiliar to Canadians.
His life style and his flair for the dramatic - wearing a rose in his lapel during parliamentary debates - attracted wide, almost un-Canadianlike political attention.
Canadian politicians are supposed to be restrained. Most prime ministers of the 20th century fit the image. But not Mr. Trudeau, nor the Liberal W.L. Mackenzie King during the interwar and World War II years.
There are many Canadian commentators who think Mr. Mulroney is out of the same mold - ''another Trudeau in the making,'' as one Toronto paper put it. In his mid-40s, he is an attractive, wholesome-looking ''Tory'' - one who emerged from working-class parentage into a successful business career in Montreal. He has flair and style.
There are numerous similarities between the present and would-be prime ministers.
Both hail from Quebec, the French-speaking part of Canada, although both clearly oppose the secessionist ambitions of many Quebec politicians. Mr. Mulroney obviously comes from British background; Mr. Trudeau from French stock. Both are bilingual, something that has long stood Mr. Trudeau in good stead and will certainly help Mr. Mulroney, as it did in his bid for the Conservative party leadership.
Actually, Mr. Mulroney makes much of bilingual fluency. The Conservatives in the past have often scorned French speakers. But they appear to be changing their tune. They certainly were attracted by their new leader's linguistic ability. They also scent the possibility of cutting into the Liberal hold on Quebec Province, which has served Prime Minister Trudeau as a strong political base.
''We seem to be off to a good start,'' Mulroney said here. ''If the Liberals were waiting for me to stumble . . . in the days after (the convention), they've been badly disappointed.''
Most Canadian political observers agree. The polls today give the Conservatives 50 percent of the popular support - more than enough to guarantee them a majority if the elections were held now. The election must take place within the next 17 months. Mr. Trudeau will have a big say in choosing the election date.
Liberals readily point out that Mulroney has never sought nor won elected office. In a nation where most politicians work their way up through the ranks, this could be a problem.
But not for long. A friend of Mulroney, Conservative Elmer MacKay who represents Central Nova, Nova Scotia, in Parliament, is vacating his seat so Mulroney can run. The by-elections are set for Aug. 29, and most think Mulroney is a shoo-in. The problem of parliamentary inexperience nearly resolved, political pundits expect his star to keep rising.
Mr. Trudeau, for his part, is doing all he can to keep his own star from falling. He and his party are trying to change their image: from economic nationalists favoring state control, to supporters of business.
''Take a look at the stands he has taken in Parliament,'' crows a Liberal supporter, ''and you can see that he is rushing to build a new image.''
In the process, he is getting some good marks from businessmen who, for example, praise the prime minister's 1983-84 budget. Gone from Trudeau rhetoric and that of Finance Minister Marc Lalonde are any suggestions of further nationalist aims. Trudeau and his close advisers repeatedly point out that they regard the private sector as the key to easing Canada out of its deep recession.
''That is mighty good news. And it is backed up by a budget that looks restrained,'' says Calgary businessman Bob Buchanan. Other businessmen agree.
There is still some question whether Mr. Trudeau will run for reelection as party leader. Many liberals expect him to step down. If he does take that step, the betting is on former Finance Minister John Turner to replace him. But at the moment he does not appear to be a leader about to retire.
Next: Where Canada goes from here.