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The last two leaders to test the limits of longevity were provincial ones. Seeking a fourth term in Quebec, Jean Charest lost narrowly and subseqently stepped down. Seeking a third term in Ontario, Dalton McGuinty won narrowly — only a minority. He retired shortly thereafter.

Next up is Stephen Harper. Time is running short for him to decide if he will gun for four in a row. If he holds off too long, he will leave his successor with no time before the next election.

If Harper turns his falling numbers around by the end of the year, he is almost certain to run again. But if he hasn’t reversed the extraordinary rise of Justin Trudeau by then, look for him to turn out the lights. He will not want to risk losing the crown to a Trudeau. For a politician whose detestation of Trudeau Liberalism dates back decades, there could be no fate worse.

On the prime minister’s future, two schools of thought prevail. One comes from the ‘blip brigade’. They see the rise of Justin and the nosedive in Conservative support as an ephemeral and perishable trend.

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The other group is the Armageddonists. In their view, doomsday is nigh for the Harper gang. The public mindset has shifted. Canadians are tired of the Harper act, they want change and there is no stopping the son of Pierre Elliott Trudeau.

The blip brigade’s thinking rests on several pillars. Though Conservative support has dropped from 40 per cent in the last election to about 30 percent now, the party always loses support between elections. The record shows it rises again during campaigns.

Harper has had a bad stretch but, the thinking goes, he will get his free trade agreement with Europe, a big cabinet shuffle will give his team a fresh look and the Trudeau honeymoon will end, as all honeymoons do.

Like most other leaders, Harper loves power and wants to keep it. If he steps down, he won’t have to face Trudeau in an election — but the perception might linger that it was Trudeau who pushed him out the door.

In addition, the Tories have much more money in the bank, they have seat redistribution working in their favour and they have the big vote-splitting divide on the left, which is not going away. Though they are being hurt by the perception that Harper is a gutter politician who will use every low-grade trick in the book to further his ambitions, many feel there is still time to fight that perception.

The Armageddonists counter that eight months of polls giving Trudeau such high numbers add up to far more than a blip. Trudeau’s made mistakes, he’s put little policy on the table, he’s been ridiculed in attack ads and still the amazing leap he has made for the Liberal party — about a 15 per cent jump in support — holds up. Not a blip, they say. Rather, a trend.

Their thinking is that the public has held the Liberals in purgatory for long enough and are ready to restore the natural order to Canadian politics by re-electing them.

Harper, Liberals feel, won’t be able to escape the sleazebag trap he finds himself in. There will be more revelations of ethical corruption. Just recently the Toronto Star revealed that the government has kept secret millions in taxpayer-funded consulting work. Results from Elections Canada’s robocalls investigations have yet to come in.

More evidence is needed, but there is a suspicion the last round of attack ads may have tipped the scales against Harper — doing more damage to his own image than to that of his opponent. No prime minister in history had ever stepped so low as to launch dishonest attack ads on the very day an opponent was elected as party leader.

There is also the fatigue factor. No federal leader has won four elections in a row since Wilfrid Laurier. In the past, Harper’s victories have been due not so much to affection for him as to dissatisfaction with the Liberal party.

The prime minister is in a most difficult position. He could leave shortly and go down in history as one of his party’s great success stories, certainly from a political point of view. But like most other leaders, he loves power and wants to keep it. If he steps down, he won’t have to face Trudeau in an election — but the perception might linger that it was Trudeau who pushed him out the door.

Harper’s decision will be based on the perceived strength of the Trudeau numbers. If they remain solidly in the mid- to high-thirties range, he’s likely gone. If they drop lower, he fights.

The decision should come no later than the end of this year. That would allow the party, should he step down, to have a convention in May or thereabouts, leaving his successor a year to establish some kind of record.

Waiting longer could be deadly for the next leader of the Conservatives. Brian Mulroney waited until his fifth year, 1993, to call a leadership convention. Successor Kim Campbell had no time before having to go to the polls. Upon his retirement in 1984, Pierre Trudeau left successor John Turner very little time as well. Both Campbell and Turner were wiped out at the polls.

But with a Trudeau in the ring, the Harper decision will be such a tough call that he may well wait quite a while longer. If that’s hard on his successor, too bad.

Lawrence Martin is the author of 10 books, including six national bestsellers. His most recent, Harperland, was nominated for the Shaughnessy Cohen award. His other works include two volumes on Jean Chrétien, two on Canada-U.S. relations and three books on hockey.

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