You have it entirely backwards. Quite the opposite of being a throwaway vote, a single “protest vote” in the presidential election is (except in the incredibly unlikely scenario of an election decided by a single vote) much more forceful and potentially influential than a single vote for either major party. While the chances of a single major-party vote having any affect on the outcome of the election are virtually zero, every vote cast for a third party (on the condition that the defection is large enough, which is a reasonable low hurdle) shifts the landscape of electoral credibility and opens the possibility of influencing the major parties’ platforms (more on this below).
A candidate wins with a bare majority of the votes. So unless the election is decided by a single vote, each individual vote for a major party is worthless —that is, you could destroy any (or many) of them, and the result would be the same. In fact, all of the losing major-party candidate’s votes are always worthless, since they all could be destroyed and the outcome would be identical. In contrast, a third party candidate (who has a very low probability of actually winning a majority) is fighting for proportion — so, even if they only get 10% of the vote, it’s clear that a third party has put itself in a position of profound influence on the platforms of the major parties (again, more on this below), since the prospect of a major party appealing to ~10% more of the population is the difference between a win and loss or a narrow win and a blowout. Of course, Jill Stein would take a win, but her goals and priorities are not the same as Trump’s or Clinton’s, and it seems unreasonable to hold Stein (or those who would align with her, since it seems that your focus is more on voters than parties) to the same standards as those major party candidates (and their allegiants).
Voting third party is not an abdication of one’s political responsibilities — quite the opposite, for the politically disaffected, it’s a far less cynical and far more responsible and sustainable manner of engagement with the American electoral system than voting in a manner that sustains and lends credibility to the status quo.
In fact, since you brought it up, voting for the “lesser of two evils” is itself precisely the end of political engagement — it’s the sacrifice of any true commitment in favor of cynical, misguided expedience. The “lesser of two evils” logic is pure cynicism and purely apolitical.
Additionally — and this is very important — if you’re going to ride your high horse in such a reckless and reductive manner, it seems reasonable to expect you to at least get the facts straight regarding the historical importance of third party presidential candidates. It’s common knowledge that a third party hasn’t won a presidential election, but third parties have had a tremendous influence on presidential electoral politics. Several points of TR’s 1912 Progressive Party platform pushed the next few decades of Democratic politics, Ross Perot’s focus on deficits influenced the Clinton administration’s balanced-budget focus, Wallace’s 1968 segregationist platform changed the Republican strategy with regard to Civil Rights, and many other issues (such as women’s suffrage, 40-hour workweek, child labor laws) were put on the national radar by third parties and eventually led to legislation— there are other examples, like the Populists. These changes were possible (1) by having third parties, (2) by a significant portion of people voting for those third parties, (3) and by having the other parties notice.
You mention Nader as a defense of your implicit (or not so implicit?) claim that third party presidential candidates don’t have a significant influence on party politics, but it was just a poor example. Yes, Nader factored into the Florida debacle in 2000 (simply because it was so close between Bush and Gore), but he received less than 3% of the national vote that year, so it’s hardly surprising that his platform didn’t really change much.
It’s also worth pointing out that in its relatively short history, the U.S. already has had at least one major party collapse — the Whigs in 1856, which opened the door for the rise of the upstart Republican Party. I don’t think it’s unthinkable for something similar to happen today (though, of course, it’s far less likely, considering how deeply the two major parties are rooted in American electoral politics).
The apolitical logic you espouse in your article might make you feel like you’re engaging the world in a reasonable and significant way, but make no mistake — if you cynically vote for a major-party candidate in November, your vote wouldn’t matter and you’d be tacitly affirming the status quo two-party system that rendered your vote meaningless.
