Trump may or may not be sincere in his humanitarianism. He may be playing a long game or reacting off the cuff. None of this matters. The important thing is he has put down a marker. He has formulated the principle that human lives matter in the pursuance of foreign policy advantage. And I don't think this has been done before. Certainly not as baldly as this. Trump speaks simply, with a limited vocabulary- and what's he's said cannot be misunderstood. Killing people is wrong. And that includes foreign people. We shouldn't do it lightly.
It's in the 10 Commandments. They teach it in the churches and the schools and almost everyone on the planet would agree with the principle- but I can't remember it constraining the actions of a US President before.
Perhaps- on the principle that only Nixon could go to China- it took Trump- a man perceived to be ruthless and hawkish- to take this step.