It’s crystal clear that there was no “imminent threat” that led the U.S. to target and kill Iran’s Qasem Soleimani. Even on logical terms that makes zero sense. If there was a plot underway to kill Americans, the way to disrupt that would be to remove the target or attack the operational chain about to carry out the attack. That’s obvious. I think we’re a long way from finding out just why this happened. But in a broad sense we know: punish Iran and assert dominance in the largely covert and shadowy conflict between the two countries.
You may not agree with that decision. But it’s not hard to understand. States have been doing things like that for millennia. The only real question is why the claim of an imminent threat. The most obvious answer is legal: lethal force to disrupt an attack is defensive and much more justifiable under the laws of armed conflict. Is it that? Or is it more political justification? Who knows?
The only thing we know really to all but a certainty is that the whole justification of imminent threats is bogus — both logically, as noted above, but also based on the administration’s inability to come up with a clear argument, let alone any evidence.