Here are a few reasons why he'll stay:
1. Stephen Harper is in his early 50s. That's awfully young to retire. And what else would Harper do for a living? Unlike most living PMs, he's not a lawyer, so he can't end up as a letterhead partner at a big firm. And he can't be a lobbyist for five years, even if he wanted to. And I'm sure he doesn't.
2. Harper's career, even as Prime Minister, was geared to winning a Conservative majority and crushing the Liberals. Quitting just past the half-way mark of the first majority would be a terrific failure.
3. Every Tory I know believes Justin Trudeau will defeat himself, just by talking. When the going gets tough, they imagine Trudeau being tag-teamed by Harper and Mulcair in the leadership debates, the same way Harper and Jack Layton crushed Michael Ignatieff.
4. The Harper family is happy in Ottawa. It's unlikely they'd stay here if Harper quit, so resigning means moving, taking the kids out of a good high school, and much more disruption in their lives.
5. Harper has never given the slightest hint that he's leaving. While he's always kept his own counsel, it's important to keep in mind that the only people who say he's going are the people who would love to see him gone.
6. Harper seems to actually believe the federal budget will be -- or appear to be -- balanced by election day. The economy should also be a bit better. Some more trade deals might be signed. That should offset some of the problems caused by the Senate scandal, which has now become so intricate that few people understand it anymore, and most of those who try to follow along put the blame on Mike Duffy and the rest of the senators who are under investigation.
I could be wrong. I'm a terrible predictor of this kind of thing. But as I work on Kill the Messengers, I grow more convinced that Harper is among the most stubborn people I've ever seen. To him, politics is applied game theory, and he's not about to walk away from the table.