<Snipped quote by Jotunn Draugr>
It's kind of a slippery slope though, isn't it? If everyone took your mentality (which may actually be correct here), then there would be no hope for the duality system ever breaking. You need to start somewhere, right?
Lol, well as it stands, nobody in America votes third-party. Everyone has taken my mentality (eesh, guess it's not much of an unpopular opinion). However, I added the caveat of a "shift in the zeitgeist" for a reason. You voting third party NOW will do nothing. But, if you vote for the lesser evil of the two major parties, and then work to change the hearts and minds of those around you, so that they align with the third party's ideology, you're setting up for third-party success down the road. Changes in the electoral process happen through personality, not polls. It wouldn't matter if Milo Yiannopoulos voted Democrat in the next election, because he's prosthelytized thousands to the Alt-Right.
<Snipped quote by Jotunn Draugr>
I always found that idea a tad narcissistic. Realistically I'll never decide an election, so voting based on the idea i'll decide an election is silly. But I can contribute to post-election statistics about independent voting patterns and groups a major party has to earn later down the line. Vote for your party regularly and nobody has to do anything for your vote because you'll give it to them no matter what, but if enough people vote for a third party then that put pressures on the major parties. So to me, I see the function of the Libertarian and Green parties in the US not so much to be winning elections and more like being ways voters can tell the parties "You are veering too far to the center and I don't like that."
It's a nice idea, and I think figures like Bernie Sanders do show how that can
almost work, but when push comes to shove, we see that the powers that be are extremely resistant to change, and would rather try to change the voters than change for the voters. What I think is the the more effective method of enacting change is actually to vote for the lesser evil among the Democrats and Republicans, and then try to convince those around you, that third-party is the eventual way to go. You're not going to win any elections right now, so you need to play the long-game, and that isn't won with just statistics from any given election. You need to set up a voting block. If you read my response to Mateotis, I give the example of Milo Yiannopoulos. Whatever you think of him, he's done wonders for the Alt-Right, regardless of how he actually winds up voting. Now let's assume a figure like Milo appeared for the Green Party. He could change the opinions of thousands of people, though sheer personality, and still personally vote Democrat in this election. That way, his vote counts toward his short-term goals (#NeverTrump or something), and he's establishing a voting block that'll become influential down the line, which is the only way you'll actually see the Green Party become a powerful force.
In Canada, we have the Communist Party of Canada. They get less than 1% of the vote, and yet a lot of the ideas that are promoted by the other left-wing parties, are first presented by the Communists. In their own words (having seen a debate with a Communist representative and some other public figures) "we do most of our work between elections, not during".
I really think that this is how you win the zeitgeist, if that's your goal.