Richard Nixon was not the lesser evil, he was the greater evil, but in his administration the war was finally brought to an end, because he had to deal with the power of the anti-war movement as well as the power of the Vietnamese movement. I will vote, but always with a caution that voting is not crucial, and organizing is the important thing.
I am not an absolute pacifist, because I can't rule out the possibility that under some, carefully defined circumstances, some degree of violence may be justified, if it is focused directly at a great evil.
I believe that it is preferable sometimes to have one candidate rather another candidate, while you understand that that is not the solution. Sometimes the lesser evil is not so lesser, so you want to ignore that, and you either do not vote or vote for third party as a protest against the party system.
What happened in World War II was what happened in war generally, and that was whatever the initiating cause, and however clear the moral reason is for the war in which one side looks better than the other, by the time the war ends both sides have been engaged in evil.