There is a fair amount of wailing and gnashing of teeth on the Arizona immigrant decision and some of the teeth are mine! But there is some useful supportive language in favor of it being unconstitutional for municipalities and local governments to conduct foreign policy. And that means only one thing: ICLEI is indeed unconstitutional for an American local government to join!
The beginning of the analysis of the Arizona decision has these words in it:
This [exclusive immigration] authority rests, in part, on the National Government’s constitutional power to “establish an uniform Rule of Naturalization,” U. S. Const., Art. I, §8, cl. 4, and its inherent power as sovereign to control and conduct relations with foreign nations, see Toll, supra, at 10 (citing United States v. Curtiss-Wright Export Corp., 299 U. S. 304, 318 (1936))
The Curtiss-Wright case is a seminal case on administrative law but it also has historic analysis that states (and by definition local governments) NEVER possessed any foreign policy power at all. The Curtiss-Wright Court held that foreign policy power passed from the British Crown to the Continental Congress to the federal government under the Articles of Confederation to our present Constitution and thus was never for one moment in the hands of the states.
The Arizona v. United States Court also cited the case of Toll v. Moreno for the same proposition: That immigration power is the sole power of the national government based on its foreign policy authority:
Federal authority to regulate the status of aliens derives from various sources, including the Federal Government’s power “[t]o establish [a] uniform Rule of Naturalization,” U.S. Const., Art. I, 8, cl. 4, its power “[t]o regulate Commerce with foreign Nations”, id., cl. 3, and its broad authority over foreign affairs, see United States v. Curtiss-Wright Export Corp., 299 U.S. 304, 318 (1936); Mathews v. Diaz, supra, at 81, n. 17; Harisiades v. Shaughnessy, 342 U.S. 580, 588 -589 (1952).
While I was hoping for a delicious footnote in the Arizona case such as “We hold that foreign policy is such a power that is exclusively within the power of the national government.” or words to that effect but the Arizona case, perhaps unhelpful in some aspects, is one more evidence that cities, towns and counties cannot constitutionally be a member of ICLEI.