I know Dimitri as a expert on Greece, but he's a partner at a Canadian corporate law firm and ran for a seat in the Canadian election with the Green Party.
He summarized the quandary of running as a third party quite well:
Well you know, I did knock on a lot the doors. I had a lot of interactions with voters through a variety of methods, including canvasing, but also online debates, other campaign events, and I was pummeled in the sentiment that we had to do whatever it takes to get rid of the Harper government. I would say that you know, some 60-65 percent of the people I spoke to were intensely hostile to the Harper government and that was their singular objective, and the strategic voting argument had a great deal of appeal to them. You know, if I had a dollar for every time I heard "I want to vote Green, but I want to beat Harper more" I would be richer than Bill Gates. I mean, it was something that was a constant refrain in the campaign, and you know, I think it's reflected in the results. The Liberal candidate won handily in her riding, the incumbent Ministry of Science Ed Holder after two terms has been soundly defeated.
The NDP candidate was a distant third, and I did not manage to improve substantially on our party's last result in the 2011 elections with 2.7 percent. I'm currently standing at about 3 percent with about 82 percent of the votes counted. so it was really the only way to describe it was a toxic environment for which a small party to operate in, this environment in which you have a "first-past-the-post" system and intense hostility to the conservative incumbent government, and everybody looking to the most viable option to defeat that government.
Unfortunately, most discussions by progressives, mirrored by discussions among conservatives, debate simply working within or outside either of the establishment parties without a real strategy.
Both these positions are wrong. The people saying you have to work with the Democratic party are entering a situation where they have no leverage -- they will end up backing whoever the nominee is and have little leverage over that person.
The ironic solution, in my view, is for disenchanted Democrats to team up with disenchanted Republicans so the bases have a chance at actually breaking down the two party system and actual victory -- and, regardless, some leverage over the party apparatus.