The US has already extrajudicialy murdered a US citizen on purpose. The US under Obama sent a drone to murder a citizen without a trial.
Precedent was publicly set then.
The US 3 letter agencies have been doing this in secret for their entire time in power. But those are widely considered outside the law but necessary. Whatever that means.
Agree but I feel like pointing that out is implying this somehow doesn't make things worse which I feel like is missing the point. This removes the implicit threat of prosecution for anything the president does.
Now no matter how much political will exists for the prosecution, the president is fully and unequivocally immune.