My philosophy is that if a candidate looks like he will advance at least one thing I really care about, while not going against anything I really care about, then he’s an acceptable candidate.
I agree with you that there will never be a perfect candidate.
The problem is that everybody “goes against” something good until they have departed the mortal coil. And if we had enough of the mind of Christ that would ironically put us in the position that we could never give the nod to a political candidate because now we would know something bad that they all would do.
We can make the best prudential move in a situation. Sometimes apparent threats do not pan out due to other factors. Sometimes people change their mind about apparent threats.
Because ultimately the situation could be worse: the person could be chosen by a committee of oligarchs and you might not even be asked for your voice. It is not as though, if you sat on your sofa, the persons asking for your vote would all go away. They won’t.