It should be clear from elementary first principles of causality that voting for Cornel West or any other 3rd Party candidate is not voting for Trump. If everyone followed the same example, Trump would not be elected, Cornel West would be. No amount of votes for Cornel West will ever get Trump elected.
Now it may be true that voting for a 3rd Party candidate is not voting strategically to stop Trump from getting elected.
I will try to parse the ethics of that.
Consider the first case, where Trump is metaphysical evil, and his major party alternative is metaphysical good.
OK, in this case why aren't you voting for metaphysical good? But this case never happens. But this is of course what every partisan is mostly going to argue. They're not going to bring up any deficiencies of their side unless they can't avoid it. Whether they concede such deficiencies the interlocutor claims may depend. Such arguments quickly become pointless because they are merely contests of rhetorical skill and guile.
Now consider a more likely case, where Trump is still metaphysical evil but Trump's major party alternative is a mixture of good and evil.
In this case, Trump is clearly a greater evil and Trump's alternative is clearly and undeniably a lesser evil.
On that basis alone, a vote for the lesser evil is for the greater good and will therefore be the better choice.
But in combination with that strategic vote for the greater good, there is also acceptance, ownership, causality, and responsibility for the lesser evil. (That itself is a complex issue to be expanded below.)
And there is also inability to discipline the lesser evil party over time, and perhaps the ability to build serious alternative parties (note that such a party needs to be on the way to becoming more popular than one of the existing major parties...fringe ideologies are unlikely to make it...what's needed for Communists is Popular Fronts--which may be near centrist in general ideology, as for example Roe v Wade was a a compromise between liberals and conservatives before "conservatives" went full on fascist.)
Now, materialists (including most often Marxist-Leninists) and other pragmatic people often write the ethical value of things like protest votes as irresponsible personal styling (self-righteousness) at the expense of material results.
Taking an inflexible stand like that is not only denying the abilities to discipline parties, build new ones, etc.
Furthermore, it deprives people of something fundamental, the ability to express themselves and take full ownership of the responsibilities of their action.
There is no question about it, voting for Biden is not only not-voting for Trump, it is also unequivocally voting for Biden.
If that bothers someone's conscience, who am I to judge?
Surely you wouldn't want to vote for a serial killer who has kept on a rampage throughout his administration and protected by that status, even if it was the only alternative to Fascism.
In this case, we have Genocide Joe, who has lavishly supplied Israel with vast quantities of bombs even while they are breaking international law and genociding 30,000 and rising numbers of Palestinians.
This is unacceptable. I will not vote for a genocider, and nor can I make any demands on anyone else to do so.
The fact is, and it's very problematic, that the US is not only not a democracy, it is not a good democratic republic either, it is an outlaw plutocratic and oligarchic warmongering empire with periodic "elections" among candidates acceptable to the deep state who are by that time fully wired up to deep state control systems including bribery (Campaign Contributions, Soft Money), blackmail (Roy Cohn, Epstein), and assassination (JFK, RFK, Wellstone).
In such a situation as living within such an entity and being forced to do the unthinkable, it might well be that the most morally valid option is ritual suicide. It can be as morally valid as anything else that could be done and far better than most, heroic may apt if the situation deserves it as it does in the case of Aaron Bushnell. But simultaneously I also strongly discourage it and so no moral principle or god could ever require it. No principle requires you to be heroic and every wise sage will counsel against it. One could also simply fail to perform the unthinkable task and then accept the resulting punishment, though it could be less heroic. Or even take a more active role opposing the evil as justice allows. However the truly heroic also have their place.
Solving our future problems will necessarily require something radically different than what we have now.
Because of that, it may sometimes be necessary to shake things up. Really shake things up.
So I think strategic (lesser evil) voting has it's limits, and they apply in spades to Genocide Joe Biden.
It could even be argued, we need to hand Genocide just a loss (which he is almost certain to achieve anyway) but a huge loss, as a denunciation of genocide.
Even though Trump may be no better, we must force someone to come up with a better option.
Finally, following on the arguments I made with regards to heroism, no god or principle can require you to vote strategically if in even the slightest way you feel upset by both choices. Everyone is perfectly entitled to vote for the actual candidate they like best, or not vote at all. No god or ethical principle requires you to (insignificantly) move the levers of US state power. You are perfectly entitled to leave the such decisions to everyone else. You are absolutely free to vote for whoever you like or it's not voting, it's forced acquiescence. Even while voting strategically to block a greater-evil candidate from power is often adviseable from ethical principles, there are other tests, and ultimately the smell test. How much filth are you putting your fingers on (and that is exactly what you are doing, not merely stopping a greater evil but announcing tolerability with the lesser one). So that is the ultimate question. How does the range of choices (and strategies) actually smell?
Whose responsibility is it if instead of the polls best representing the feelings of people is not best achieved by each person voting with their feeling? Well to some degree it may include the voters as much as they are being irrational. But in larger part it is the fault of the designers and maintainers of the political system and those who wield power in it. Blaming the people for voting their feelings is blaming the victims.
Your input has essentially nil effect anyway, it's hardly worth the trouble of voting usually, though most often I do (and most often following lesser evil Popular Front principles, voting Democratic).
In US discourse, the importance of each persons vote is way overamplified. Even collectively, the mass of public voting has only 11% effect on government policy. Our "republic" largely runs on capitalist and deep state power. Futhermore, the effect of our republican system is to insulate existing power, most districts and states are not politically in play, not even remotely. The chance of affecting them is smaller than small. Only a few districts and states are poltically in play even among the exising major (and deep state owned) parties.
3rd party voting is usually materially and politically better than not voting because it reveals an underlying preference. This is sometimes of importance, as reflected in the toungue lashing often doled out to 3rd party voters.
I am also disgusted by the endless US arming of Ukraine after provoking a war there and rebuffing pre and post invasion Russian settlement offers. Many people see that issue differently than I do, they think Biden is defending Ukraine. I see it as an imperial proxy war, with Russia defending ethnic Russians in historic Russian lands that got conglomerated with western leaning lands.
While much more total death and destruction has been caused by US meddling in Ukraine, the skill of fighters on both sides is such that the actual number of civilian casualties is far less than what has been seen in Gaza, a far smaller area.
As Scott Ritter explains, the Israeli army is very unprofessional, they know how to blow things up and murder civilians but little else. They are even losing the war militarily (not just in world opinion). Scott also praises the planning and professionalism of the hamas attack of 10/7 saying it will go down in history as a miracle of resistance warfare.