"THE President is to have power, ``by and with the advice and consent of the Senate, to make treaties, provided two thirds of the senators present concur.'' - Federalist #75
"However proper or safe it may be in governments where the executive magistrate is an hereditary monarch, to commit to him the entire power of making treaties, it would be utterly unsafe and improper to intrust that power to an elective magistrate of four years' duration." - Federalist #75
"He shall have Power, by and with the Advice and Consent of the Senate, to make Treaties..." - U.S. Constitution - Article II, Section 2
"First. That the supremacy of the national power in the general field of foreign affairs, including power over immigration, naturalization and deportation, is made clear by the Constitution was pointed out by authors of The Federalist in 1787,9 and has since been given continuous recognition by this Court." - U.S. Supreme Court, HINES v. DAVIDOWITZ
P.S. - I'm not a lawyer ;)
On another thread with George, I believe we're down to whether the Supreme Court has the power to interpret the Constitution. But the question of whether such delegation has been done in the past by Congress and has been upheld by the Supreme Court is over.