In the US, laws against assassination and extrajudicial killing make no distinction between American citizens and others: Foreigners have the exact same protections as citizens. This goes for the Bill of Rights as well. (Aside, this explains why the NSA is only "supposed" to spy outside of the US. Wether the target is a citizen or not is technically irrelevant on this particular point) If you accept that the US is in…
The worst case scenario message being sent is that if I or a fellow American steps outside our land, the executive can decide to blow us away, based on evidence they provide. Judge, jury, and executioner. Literally. But it doesn't really matter if the executive provides a photo of an American holding an AK-47, a court needs to decide if the citizen is a traitor or not (and i'm giving them the benefit of the doubt that they'd provide at least that much evidence, which ,actually, legally, I would think still isn't much).