Ontario Tories in leadership race

The race is on to see who will be the next premier of Ontario, Canada's richest province. Ontario's Progressive Conservative Party is going to choose a new leader at a three-day convention in Toronto in January.

Premier William Davis resigned after 25 years in provincial politics but will stay in office until after the leadership vote. He has been leader of the party and premier since 1971, and his party has been in power for more than 40 years, a record for political longevity in Canada.

The Ontario Tories have been in power so long because they have fine-tuned the art of political compromise. Many of their policies have shocked small ''c'' conservatives, and the mildly socialist New Democrats have long accused the Conservatives of stealing their ideas. That is how the Conservatives have remained the ruling party since 1943 - by playing to the center of the political spectrum rather than to the extremes.

Bill Davis is the most popular politician in Ontario, and the latest opinion polls give his party 56 percent of popular support. Many of his advisers urged him to call a snap election this fall. Instead he decided to resign.

The ''Big Blue Machine,'' as the Ontario Conservative Party is known, has been unstoppable when it starts to roll at election time. Davis threw the support of his political organization behind federal Conservative leader Brian Mulroney in the recent election.

Davis has not always been so kind. In the 1980 federal election he all but ignored Joe Clark, then Conservative leader, because Mr. Clark - a westerner - appeared to favor the province of Alberta in its battle over higher energy prices, which would hit Ontario consumers. Joe Clark did not carry Ontario - or win that election.

The man - so far only men have shown interest in the job - who is elected leader of Ontario's ruling party will automatically become premier of Ontario, Canada's most populous province and its manufacturing base.

There are two front-runners in the race. Larry Grossman, the provincial treasurer, has the support of many in the Big Blue Machine. Ambitious and hard working, Mr. Grossman has made few mistakes since entering politics nine years ago. The second, Provincial Attorney General Roy McMurtry, has yet to announce his candidacy, but he is backed by Norman Atkins, who managed Mr. Mulroney's race. Other contenders include Cabinet ministers Frank Miller and Dennis Timbrell, and former provincial Treasurer Darcy McKeough.

The opposition parties have been given a reprieve by the Tories' leadership struggle. If a vote had been held this fall, they might have suffered heavy losses. Now they can hope a new leader will be weak, a compromise candidate for a party of compromise. But then Bill Davis was seen as a weak when first elected - and he's leaving the party in a stronger position than when he inherited it.