Distilled down to a pithy saying, I think a good moral foundation is something like: One may never morally commit an evil act for any reason, even if that act

Distilled down to a pithy saying, I think a good moral foundation is something like: One may never morally commit an evil act for any reason, even if that act will prevent an even greater evil from being perpetrated. That "will" is tricky, because often you don't actually know what the outcome will be, but I think it applies even if you do know with certainty. Forgive my following ramble: This is hardly a new thought - it's one shared by a number of religious belief systems (Catholicism comes to mind, CCC 1753 explicitly says this in about as many words), but there's a lot of wisdom to be had with this even if you completely write off the religious angle. It completely removes this possibility. The avenue is forever closed; if you reject evil acts, no ifs-ands-or-buts, no ends justifying the means, this is simply never a thing you'll accept or allow yourself to be involved with. It's simpler as far as moral thinking goes, it removes a lot of judgment, which is usually a red flag for lazy reductionism, but given the sheer quantity of evil in the would of the banal sort, exactly as you described, I'd wager that the world would be a better place overall if this principle were followed by good-faith actors.