Was it Legal?

OK, so the question is: Was the U.S. assault on the Iranian consulate in Irbil–sovereign Iranian territory–legal? Does the President have the power to invade another country without authorization under the war powers act? I would think not, but I just spoke to a Democratic Member of Congress who was freaked by the obvious attempt to provoke the Iranians into a military response, but said that it might have been legal if the people and information seized were directly involved in attacks on U.S. citizens. Does anyone out there have a clearer sense of the legal issue here?