In bragging that he ordered a successful hit on Iranian Maj. Gen. Qassem Soleimani, President Trump has admitted to killing a senior government official of a sovereign state, Iran, while he was traveling in another sovereign state, Iraq. On its face, his conduct and intent satisfy the elements of premeditated murder under Section 1116 of Title 18 of the United States Criminal Code, “Murder or manslaughter of foreign officials, official guests, or internationally protected persons.”
We can and must debate, and many are, whether the killing was an “assassination” or a violation of “international norms,” but neither of those charges has been codified by Congress into the criminal code and thus they have no teeth. The assassination ban is found in an executive order and a president is not bound by it. As for international norms, including the adherence to long-standing principles of the ethics of just war, well, ignoring norms is Trump’s calling card, and his supporters love him for it.
The provisions of the United States Criminal Code, however, bind all persons, including presidents. They cannot be waived, and they have very sharp teeth. By ordering the drone attack killing General Soleimani, it appears that Trump committed a homicide under federal law.