The ethics of John Yoo, revealed to a Justice Department interviewer. This is the OPR report at page 64 (70 in the PDF):

Q. What about ordering a village of resistants to be massacred? …Is that a power the President could legally –

A. Yeah. Although, let me say this. So, certainly that would fall within the Commander-in-Chief’s power over tactical decisions.

Q. To order a village of civilians to be [exterminated]?

A. Yeah.

This is the deputy chief of the Office of Legal Counsel at the Justice Department averring without hesitation that the president can legally authorize what is universally accepted to be war crimes.