The Moral Obligation to Choose the Lesser Evil

[Sal]

I agree with the premise. But moral "math"? That seems like a stretch.

It's pretty straightforward, really, just thinking about morality like we think about any other thing.  The item in question comes down to what we do when presented with exclusively suboptimal decision fields. The rule is simple.  Whichever Y is less than Z, is X.  Where X is the moral decision - the Proper Answer™, Y is the moral weight of a decision, and Z is the moral weight of any competing decision.  

Does that sound like something you use in your own moral deliberations?

I agree with the premise insofar I'm able to distinguish between two choices (regardless if there are more choices present, it's not pertinent if the choices are binary or if there are more - there might be more, but being presented with two viable choices and conclude it's between two viable choices). I just think the stretch is when some sort of calculation is made. It might be quantifiable like in the OP (Trump's asshole factor being greater than Biden's asshole factor for the US election), hard to say.

I think it's too easy to determine there is some course of action associated between such two choices, unless it can be demonstrated. In a political sense, you're choosing between two people. How the hell do you know what action they will take once chosen? Are you a mind reader?

I do think that when considering harm from two or more choices of actions it is quantifiable, but that's the expected impact of your own actions. However, in this regard, it's pretty safe to infer that Trump's actions in office will be worse than Biden's because of the history of actions of the two.