To be honest I'd rather live in a world where Obama¹ assassinating an US citizen would land him and everybody involved in prison than in a world where it does not.
I assume you are referring to the killing of alleged al-Qaeda operative Anwar al-Awlaki in a drone strike. The major difference between that situation and the situation going forward is that Obama had a legal justification. Assistant Attorney General David Barron justified the action as follows [1]:
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To justify the Awlaki killing, Barron relies heavily on the 2001 Authorization for the Use of Military Force (AUMF), the law that Congress passed to permit striking al-Qaeda post-September 11th, and which was used to justify the US-led investigation of Afghanistan.
Awlaki, according to Barron, was a leader in al-Qaeda's Yemen-based branch, which is known as al-Qaeda in the Arabian Peninsula. The intelligence supporting this claim is redacted from the memo. But Barron claims that, because Congress authorized using "necessary and appropriate force" against al-Qaeda, the AUMF would thus give the US legal cover to target Awlaki.
"In consequence," Barron concludes, "the operation should be understood to constitute the lawful conduct of war and thus to be encompassed by the public authority justification." He also writes that the AUMF argument makes the killing justifiable under international law as a defensive use of force.
One possible counter-argument is that this is unconstitutional: the Fourth Amendment generally prohibits the killing of US citizens without due process of law. Barron argues that this case is an exception because capturing Awlaki was impossible — for reasons that are again redacted. If capturing Awlaki was "unfeasible," as Barron says, then killing him to prevent him from threatening the US becomes the only option.
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You may disagree with that interpretation of the law, but it seems — given that Obama was not prosecuted for this action — that the legal system does not agree with your disagreement.
Now the point is moot, since any president can order up the killing of anyone they like, because there is no longer a consequence for criminal behaviour. If you think the al-Awlaki killing was unlawful, I hope that you are gravely concerned by the fact that administrations no longer need to even attempt the appearance of complying with the law.
Drone strikes against combatants aren't assassinations, and Obama is hardly the first President to engage armed force against someone the U.S. recognized as a citizen but who felt no personal loyalty to the U.S.
When that American is fighting in a foreign force and aiding actively against US/alied armed forces as a combatant? Yeah I think that’s okay. You can’t hold off on a military target because some American mercenary is there. Those are the chances you take as a mercenary. We’re discussing a president who can now kill anyone he wants with Seal Team 6 and not face any repercussions ever, unless impeached, well I hate to say it but the current MAGA party will never impeach Trump under any circumstances.
