politicians do not call elections any earlier than they have to unless they think they are almost certain to win
If you're a majority government, I'd agree with that. But if you can't count on being able to serve a full term and think your chances are better now than a year from now when the other parties might decide to pass a no-confidence resolution then I could see someone chancing it. I'm sure British Labourites wish James Callaghan had called an election in the summer of 1978. Of course a 1978 election would have only been a year +/- before the deadline so it wasn't quite the same situation. But basically, when you don't have exclusive control of when the next election is, the calculations you have to make are different.
Oh, now I see you had already alluded to that possible analysis of Marois's below:
Maybe she figures that a 25% chance of winning in December is better than a 5% chance of winning in 2014 - but we shall see.
