Not impossible. Not complicated.
Shortly after the formation of the US we declared war and went to war against the “Barbary Pirates”. Not a nation state, as far as I know.
Obama wants a blankcheck authorization? We should go him one better and have a Declaration of War against ISIS, ISIL whatever, and any organization or state that provides them with material support. As CIC he works for Congress and the people.
That's very good. I like that.
Notice how, on December 8, 1941, it was Congress giving orders to FDR:
"Therefore be it Resolved by the Senate and House of Representatives of the United States of America in Congress assembled, That the state of war between the United States and the Imperial Government of Japan which has thus been thrust upon the United States is hereby formally declared; and the President is hereby authorized and directed to employ the entire naval and military forces of the United States and the resources of the Government to carry on war against the Imperial Government of Japan; and, to bring the conflict to a successful termination, all the resources of the country are hereby pledged by the Congress of the United States."