I consider myself an external observer to this, since I am not a citizen of either the US nor Iran, and have little interest or emotional investment in politics.
It is striking to me that no one mentions the ethical dimension of this. This person - regardless of what he may or may not have done - was a human being, and as such has the basic right to life, and to a fair trial, as we all do. How can it possibly be ethically acceptable that anyone - regardless of his rank or position - can order the blatant killing of another human being, just like that? What Trump has done is akin to me hiring a contract killer to get rid of someone I don’t like; if I did that, I would be brought before a judge, and locked away for life, quite regardless of who the deceased person was or what he/she has done. And quite rightly so. Why do these same standards of law, justice, and human rights not apply to the President of the US? Why do they not apply to other heads of states, who commit similar crimes against humanity? At the very least, this Iranian general would have been entitled to a fair trial before an impartial judge. What happened here was premeditated murder, plain and simple. If this act was illegal under US law, then Trump needs to be held accountable for his action to the full extent of the law, like any other citizen would; if it was legal under US law, then that means the US has deteriorated to a point were human rights count for nothing, and lives are expendable for political gain and leverage. If someone is in the way, just have him killed, no need to bother with fair trials.
Just to be clear, this is not exclusive to the US, it applies to anyone who acts with impunity in the face of basic human rights. If politics have become more important than life, then humanity is in a bad state indeed.