If you must vote just one way in order to Save Democracy, then of course you don't presently have the thing you are claiming to try to save, because Democracy involves choices...not just one choice.
Pondering this at long length this year, I've decided to make a break from my previous Marxist-Leninist teleological approach (and you can check out People's World today from my sidebar and see how curiously they support Biden unconditionally yet oppose many of his policies usually without mentioning him).
Though I'd framed myself since 2001 as a loyal Democrat and as such I even worked as a Precinct Captain until the Texas Democratic Caucus Disasters of 2008 and other crapola led me to conclude I'd served my time. But I continued to attend some Senate District meeting, enough to go to the Texas State Democratic convention in 2016, making the second Convention I'd attended...
All this has led me to believe that political "parties" in the USA are basically fake. At the bottom they are filled with aparatchiks from every organized special interest, along with rather few concerned but also usually very naive citizens who generally only follow the good news about their "party". But the whole apparatus is really run from the top, like an unending corporate pep rally the higher you get. At the State Convention, you can squabble in pretty much ignored special sessions, but then the big wigs put on a media blitz to make you completely numb and uncritically accept the current crop of corporate politicians.
So really it's run by the politicians, who themselves are run by the powers that be, the Plutocrats and Oligarchs.
There's hardly any good reason to participate in such a farce, though I suppose if you have the stomach for endless frustration, you can be a nice Mr Smith as much as you dare and can squeeze in to the dialog, though it will be promptly forgotten. A few people may hear you briefly.
Electoral Politics isn't really politics at all, it's a vast machine run by the real powers to make people feel good. And if they can steer you into one of the only potentially winning choices, which are both predetermined to be acceptable to the powers that be, so much the better. Ultimately it's a mind control system, making you feel like you "own" the mostly horrible decisions the powers that be are making, at least if "your" party got into power this cycle (though in many areas, especially defense and foreign policy which is the federal government's #1 role, little change is on offer and little change is observed).
As many say, if voting made any difference, they'd make it illegal.
What to do under such circumstances?
Some opt for not voting. For not participating in this sham system.
I see nothing immoral or illogical in that. But it's indistinguishable from apathy, from not being political at all, for not caring about what society does. It is not clearly communicating that this system sucks, and how it sucks in particular. It's an expression of your feelings, but possibly not the most intelligible one.
I've come to the belief that, the best thing to do is to not vote tactically at all, but to simply vote for whoever or whatever you actually believe in. Whoever best represents your POV. Isn't that what you are supposed to be able to do in voting? The results, they hardly matter anyway. It's a system problem if those feelings aren't properly communicated to the powers that be, not yours. To your own self be true!
Sadly, once again, those results may not be intelligible if you do not vote for either a listed candidate or a certified write-in. But that covers a broad spectrum in many cases, far less restricted than the Duopoly. In Texas I can vote for Jill Stein as a listed candidate, and Cornel West and Claudia De La Cruz as certified write-ins, all of whom are fine people and would not continue the genocide. Voting my feelings I have a glut of choices.
Voting your true feelings may feel especially correct where there is a large moral dimension involved, such as participating in a mass murder, war crime, or genocide. Even if the alternative likely-to-win candidate also promises to do so, it is not morally as bad as doing it right now in deontological ethics.
People would readily grasp this if they were asked to vote for someone who just murdered their entire family, in order to "save democracy."
Real politics is changing people's minds. Real politics is showing people things they did not know. Real politics is speaking out for positive ends at every opportunity. Real politics is thinking about and doing something about the future other than trying to get another corporate candidate elected. It's barely worth voting at all, but when you do, it's fine that it be an accurate representation of what you actually believe, that is to say, real politics.
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I still do recommend, both tactically and for real merit (in a few cases), voting for Democrats in the Congressional races. That's where there is some possibility of making a difference, though still not much. And this is unless you have a particularly outspoken pro-Genocide candidate, like Fetterman. It's fine to send the worst back to the farm.
Likewise, voters in swing states, where the election might end up being decided by mere hundreds of votes, might upweight the importance of voting tactically for the lesser evil. There is still no moral or logical reason to need to do so. You, the voter, are not really wielding the power. You are registering your thoughts and feelings to the system, which reframes the illusion according to such results.