[vezzy-fnord]

In U.S. politics (and I suppose generalizing to other majoritarian voting systems), the only realistic option for a major party shift to occur is a schism in the ruling dichotomy - as happened with the Whigs being torn on issues of slavery and fizzling out to Republican and Democratic. Or, more recently, the Southern Strategy morphing the Republican Party's platform into a more populist one, taking over the role of the Democrats prior to the 1960s, and dramatically transforming the formerly blue Deep South into a firmly red bloc.

Trying to break a third party in any other way is remarkably difficult, as a result of the inertia caused by reasons I listed previously. It's been engineered this way for well over a century by now.

Until you reform ballot access laws, introduce proportional representation on the federal and state level (which will break so much shit it's not funny) and have fairer debate coverage, trying to wrestle in third party candidates through mere vote will be exceedingly implausible/impractical.

Entryism, I suppose, is another option, though it has not been used effectively at all thus far.

[eli]

Here's the thing with voting: the person with the most votes wins. Even if they're a third party candidate and even if they weren't "supposed" to win. I think this is a really cool!

There are examples of this happening. Surprise progressive wins. The system doesn't make it easy, but it's possible. It will happen again. But it's a whole lot harder when their supporters choose not to vote.