I can see that point of view, but there is another. Iraq is a sovereign state, the US ignited bombs on its surface . That is an act of war against Iraq,and the US action would normally be called terrorism. The US is not at war with Iran,as far as I know. Such action has not been authorised by the US Congress. So the excuse of being at War does not work.
The proper action was for the US to request extradition from the Iraqi authorities for this gentleman,if they had evidence that he was plotting or had killed US servicemen . One might argue that this would not have been honoured, but it would gave curtailed movement.
Now plotting to kill servicemen of other countries is not a crime..Its what the DoD , NATO and the WarOffice do everyday. Killing servicemen, outside of clearly defined war zones ,and before hostilities have been declared is murder.
No the international community must condemn this action, and demand the rule of law.