Indeed it is the most obnoxiously hostile act somewhere between bullying and license to kill bounty. I would like to know how the system works because certainly the US is not the only player.

Is it really a case where Trump can willy nilly list whoever he wants, and all allies are obligated to obey without question? Is there no mechanism by which Italy or the UN can say “hold on, we are not going to accept Trump tagging his political adversaries as terrorists and then lick boots unconditionally”? Anti-terror policy is losing legitimacy with every abuse of it, including Trump’s assassination of drug dealers under the abusive claim of “narco-terrorism”.