The use of force in Syria is illegal under US law because Syria has not attacked the US and Congress had not declared war.

Armed force that is illegal under US law would be illegal under international law, because international law presumes that the use of force be lawful under both sets of laws.

A nation cannot comply with international law by violating domestic law and still have the use of force deemed “lawful”. Any US president who orders an attack on a non-aggressor nation commits not merely an impeachable offence, but also the crime of premeditated murder if even a single soldier died as a result of the unlawful attack.

International law has never accepted the concept of “Responsibility To Protect” in the absence of a declared war. The Geneva Convention, where the occupying power has a responsibility to protect civilians from military attack or abuse, are rules of war. In Anglo law, no bystander has any legal obligation to assist an injured victim; no nation has any obligation to assist citizens of another nation in overthrowing their government. There is no “responsibility to protect” and never has been any. It is pure fiction – an invention to justify conquest.