There is something called nuance. Does your vote matter? In many cases it does. Does it always? Of course not. Does it always have the effect you intended? Also of course not. Let’s go through some examples.

You’re in a first past the post election system in a tight race between the main two candidates and your preferred candidate has zero chance of winning the election. One of the major candidates holds positions closer to your own but they are doing something you find pretty shitty. The other major candidate would absolutely do the same but even worse and has positions you find horrible. You take a principalled vote and vote for your preferred candidate who has no chance of winning. The candidate you find to be worse wins. Voting for the major candidate who is closer to your positions is important here. Taking the principalled action made the situation you didn’t like much worse and you have someone in office withe horrid positions on issues. The major candidate who lost takes a look at their shitty action and realized that they lost some votes for it but sees that they would lose more votes if they did not do it.

You’re in a first past the post election system and the plurality of voters suggest which candidate a few electors vote for. History and polling show that the election is not going to be close at all and one of the candidates is going to win by more than 10%. Same candidates as the other situation. The importance of your vote is pretty minimal in this specific election because your vote has little chance of affecting the outcome. Feel free to do a protest vote.

You are in a place where there is ranked choice voting. Rank candidates to your heart’s content.

Most people are in the second category, a good chunk are in the first category, and a few are in the last one. If you are in that second category and you don’t see the point in voting for a presidential candidate or want to vote for someone with no chance, go for it. If you are in a swing state, vote strategically by voting for the candidate who has a chance that most closely fits your policy positions. If you are lucky enough to be in a state with ranked choice, put who you want as your top choice then rank down the line.

Candidates are not just one issue. So yes, your vote can be simultaneously important to swing an election but you may also hold a position that is unimportant enough so as to be ignored in the party platform. No candidate can have the perfect position for every single voter. As a for instance, I support Medicare for All and have volunteered in campaigns pushing for it locally. I have voted for candidates who do not support it but the candidate they are going against wants a system extremely far away from anything resembling Medicare for All. Sitting the election out or voting for a candidate with no chance means that the candidate who is furthest from my policy position has a better chance of being elected. Not only that but the candidate getting a better chance at winning also wants worse environmental protections, worse worker protections, worse healthcare for women, worse rights for the LGBT community, etc. If your chosen progressive candidate does not win the primaries, vote for the most progressive candidate who can win the general election. Until our voting system changes, that is the best we can do. Thankfully there is at least some progress in changing voting systems like in Maine and Alaska but it is not an option for most.