From heady Trudeaumania to citizen Pierre

For the intellectual and sometimes moody Pierre Elliott Trudeau, today is his last full day as prime minister of Canada. In leaving, he got two going-away presents - gardening tools and a white-water canoe. He plans to take it easy in retirement.

The man who became prime minister when Lyndon Johnson was President of the United States, and Charles de Gaulle ruled France, drolly described his time in office: ''If you want to have one word to characterize the whole period, I would say that in these troubled times 'I survived,' which is not bad for a politician.''

Mr. Trudeau has no real plans for retirement. He and his three young sons will live in Montreal in an art-deco house on the side of a mountain. ''I can honestly say that my only resolve is to do nothing apart from the material occupation of moving from Ottawa to Montreal and finding schools for my kids, buying a new car, and hiring a maid and all those things,'' he said at a press conference.

He does not rule out some return to public life.

''I would like not to involve myself either internationally or nationally for a good period of time so that when I do get bored with myself - which may take a long time - . . . I will be free to pick and choose among the best offers, if there are any coming.''

After running Canada for almost all of the past 16 years, Trudeau's last days in office have been hectic - the economic summit in London and last-minute work on two of his favorite themes, bilingualism in Canada and world peace. Amid all this, his Liberal Party has been preparing to replace him. Tomorrow, the party convention will elect a leader who automatically becomes the new Canadian prime minister.

Last week at the London economic summit, President Reagan and Trudeau were reported to have exchanged strong words about peace at a private meeting. Trudeau's peace initiative has not been a success, and some officials in Ottawa grumble that one reason for that is American indifference to the plan. But after the summit last week, Mr. Trudeau said there was some hope for peace even if his plans for an East-West peace summit had not materialized.

''Hopefully we are beginning to understand that they (the Soviets) don't want a war, either,'' he says.

Pierre Trudeau's last domestic political offensive was to ask the Province of Ontario to officially recognize the rights of its French-speaking citizens and become a fully bilingual province.

''It would greatly strengthen the bonds of nationhood,'' the prime minister wrote in a letter to Ontario Premier William Davis. ''Its value for the Canadian spirit should not be underestimated.''

The Ontario government has not given full language rights to its more than 500,000 French-speaking residents, although it has provided some services, notably French in the courts.

It was this issue of national unity that brought Pierre Trudeau to Ottawa in the first place when he was elected a member of Parliament in 1965. His vision captivated Canadians. He was elected leader of the Liberal Party in the summer of 1968 and won a general election that same year. Those were the years of Trudeaumania, the prime minister as a matinee idol.

His political honeymoon came to an end in many ways with the October crisis of 1970, in which a British diplomat was kidnapped in Montreal and a Quebec Cabinet minister was murdered by another terrorist gang seeking a separate Quebec. The prime minister won the approval of most Canadians for his cool handling of the crisis but was criticized by civil libertarians for invoking the War Measures Act, which temporarily removed many civil rights.

Mr. Trudeau's greatest success was the bringing home the Canadian Constitution, finally breaking the last official colonial ties with Britain. Although Canada has been fully independent from Britain for more than half a century - depending on which historian you ask - any changes to the British North America Act, as the Constitution was called, had to be made in London. The reason it had not been brought back earlier was constant squabbling among the 10 provinces. But on April 13, 1982, Pierre Trudeau gave Canadians their own Constitution along with a Charter of Rights. Historians say he will be remembered for this more than anything else.

His biggest failure has been the economy. The unemployment rate is high, more than 11 percent, and Canada's economy has not picked up as quickly as its southern neighbor following the recession. His critics say that Trudeau's economic policies are to blame for Canada's woes.

The sluggish economy has certainly been a big factor in the prime minister's public unpopularity, one of the main reasons he decided to step down this year. But Trudeau and his government have been putting the blame on Ronald Reagan's policies and the spillover effect of high interest rates in the US.

''If interest rates in the US go up, it will be impossible for Canadian lenders not to seek higher interest rates, and therefore interest rates will go up in Canada,'' he says.

Relations between Canada and the US - the two biggest trading partners in the world - have been cordial but never warm during the Trudeau years. The prime minister tried for a European trade connection to lessen Canada's dependence on the US, but geography proved stronger than ideas, and the two countries are now growing even closer in terms of trade. Any successor to Trudeau is expected to seek closer diplomatic and economic ties with the US.

The man who is the front-runner to succeed Trudeau is John Turner, a former finance minister who had a falling out with Trudeau over his economic policies in 1975. In an election which could come this year, the new prime minister would be either Mr. Turner, assuming he wins tomorrow, or Brian Mulroney, the Conservative leader. Both are businessmen and will move the country to the right.

Trudeau was always happier in the world of ideas than in the world of finance. His administration has brought in many social programs.

''Good,'' say his supporters, mainly in the Liberal Party. ''Bad,'' say his critics who complain that heavy government spending has wreaked havoc with the economy and is the main reason for the devaluation of the Canadian dollar.

Since John Turner left the Liberal government nine years ago, the Canadian dollar has fallen from $1.03 in American money to 76 cents today.

Another achievement of Trudeau's was that he strengthened the political power of the prime minister, which sits in the Langevin Block across Wellington Street from the House of Commons. His critics - especially the conservative MPs - say that in making the office so powerful, Trudeau made Parliament itself weaker and less effective.