In the law, there's this idea called the "last clear chance" doctrine.
If you are in an accident, and you had the last clear chance to avoid the accident, then you are, at least in some portion, responsible for the accident.
For instance, if you are driving and a car pulls out in front of you, and you could've slammed on the brake but do not, you're responsible for that, even if the turn the other car made was illegal. Moreover, you might be held partially responsible for the other person's injuries, depending on how things work in your location.
This is even true if you can merely mitigate the damage. If you have a chance to limit the damage -- again, let's say you don't brake and the result is a collision at 40MPH instead of 10MPH -- the additional damage you cause could be considered your fault.
To me, this seems very applicable to voting.
The two parties in the US are going to put a couple of candidates up in the next few months. Both of them might be dangerous. But in the end, everyone who can vote is going to have one last, clear chance to avoid, or at least mitigate, damage.
It sucks that both parties are out there driving like maniacs.
But the fact of the matter is, they've put us in this position. And if you don't put on the brakes -- that is, at least mitigate damage -- you are responsible for the additional damage caused.
In the national elections, a choice not to vote for Biden is a choice not to brake when some jerk pulls into your lane. And if there's an accident and a lot of damage -- to voting rights in general, to reproductive rights, to the health and safety and life of trans and other queer people, to education, to the environment -- then you are responsible for not attempting mitigation.
You have the last clear chance to minimize danger and damage. And while you can yell until you're blue in the face that the Democratic party put you in that position in the first place by not running another candidate, you are still responsible even if you try to abdicate that responsibility.