>As chief executive, is bound by the Constitution to protect the States from invasion. Article IV, Section 4
You stole my answer!
But, in addition to that, there is the ‘Gunwalker’ incident which is actually a violation of international treaty... Obama could be impeached to find out if he knew of, approved, or authorized it.
I guess we could add the fact that he also is in violation of our law for supplying AK47s to the drug cartels who used them to kill a federal agent in Mexico, but then again what law is it he would be in violation of?