There are different reasons for voting. One is to support the party you like best — that is, to vote “on principle,” whatever the consequences, which sometimes means the candidate you support has no chance of winning. This, you might say, is a vote from the heart, expressing one’s convictions, despite the lack of practical impact.
A second reason is to vote in the hope of defeating a party that you actively dislike. To do this often means abandoning your first choice and going for your second or occasionally even third choice, if one of these parties has the best chance of preventing “the worst” from happening. This, alas, is the messy way politics frequently works. Thus in parts of Anglophone eastern Canada many NDP sympathizers will have to consider voting Liberal as the only feasible way to defeat a Conservative.
In Kootenay-Columbia, Green and Liberal supporters are in a bind. Their leaders have shown considerable strength and each has put forward some credible, thoughtful, and progressive policies. But there’s no way that either can win here. It makes sense that Conservative David Wilks has let slip a few kind words for the Greens, for every Green vote increases his chances of re-election.
Take just one major issue — the environment. The policies of the Greens, Liberals, and NDP overlap to some extent. They share certain environmental commitments — commitments that are almost entirely rejected by the Conservatives. Elizabeth May has acknowledged that either a Liberal or NDP government would be an improvement on Stephen Harper.
Political principles are fine, but sometimes sticking to them too rigidly is simply a way of maintaining the status quo.