At Opinio Juris, Peter Spiro and Julian Ku discuss the oral argument in the Arizona immigration case, inspiring two comments on broader constitutional questions.
First, Professor Ku notes, under the title The End of Federal Foreign Affairs Exclusivity?, that there was essentially no discussion of a "dormant" foreign affairs argument -- that is, the idea that the state law might be unconstitutional (as opposed to merely preempted by inconsistent federal law) as an interference in foreign affairs. He writes:
I just don’t think, taken as a whole, that the Court showed any deep concern with the threat to foreign affairs or to the federal government’s control of foreign affairs. The Court was focused like a laser beam on the language of the statute and how it would work in practice in tandem with existing federal law. Broad claims that Arizona was interfering with foreign affairs, and that foreign affairs are exclusively vested in the federal government, were pretty much ignored and brushed aside.
In our book Taming Globalization, John Yoo and I argue against a broad foreign affairs preemption power, especially a dormant preemptive power. While we accept that the federal government can preempt most state activities, we would require some explicit statutory intent to do so, or an unmistakeable executive policy or agreement. My bet is that, even if Arizona “loses”, an exclusive federal foreign affairs power will not emerge in this case.
(For a version of the foreign affairs exclusivity argument applied to the Arizona case, see this Slate essay by Vanderbilt History Professor Paul Kramer.)
I agree with Professors Ku and Yoo on the lack of foundation for a dormant foreign affairs doctrine, at least as a textualist/originalist matter. (Chapter 13 of The Constitution's Text and Foreign Affairs, and my earlier article at 75 Notre Dame L. Review 341). While there are additional wrinkles to the argument, most obviously Article I, Section 10 lists an array of foreign-affairs-related things the states cannot do. That is a pretty clear textual implication that (most) foreign affairs related matters not listed in Article I, Section 10 are not constitutionally precluded. If there were an across-the-board constitutional prohibition of states acting in foreign affairs from some other constitutional source, what would be the point of specifically saying in Article I, Section 10 that (for example) states could not enter into treaties?
I don't think an implicit rejection of dormant foreign affairs preemption in the Arizona case would settle the matter more generally as a modern matter: there are state activities that are much more intrusive into foreign affairs and much less justified on the basis of local concerns, so the doctrine could well survive elsewhere. And while it lacks foundation in text and original meaning, it rests on the (dubious) 1968 holding in Zschernig v. Miller. But not applying it in the Arizona case is a step in the right direction (or, at least, an avoidance of a step in the wrong direction).
Second, Professor Spiro says, somewhat in passing, that "the Founders ... had no views of any kind on federal control of immigration, the power over which is not found in the Constitution itself." Perhaps so -- Professor Spiro is a leading authority, so I hesitate to disagree. But as a comment to his post points out, Article I, Section 9 states that "[t]he Migration or Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by Congress prior to the year one thousand eight hundred and eight..." Of course this clause was principally a euphemism for prohibiting the slave trade, but as written it's not so limited, and it seems heavily to imply that Congress has power to prohibit "Migration" of persons into the states after 1808.
That raises an additional question, though: where does the power come from? (Professor Spiro is of course right that it's not granted expressly). Perhaps Article I, Section 9 is sufficient on its own, but the clause reads less like a grant of power than a limitation on a power previously granted. A common explanation is that the power comes from the naturalization clause of Article I, Section 8 -- but I doubt that as well. Regulating immigration and providing for naturalization are distinct powers. There's no necessary connection between immigration and naturalization, as Congress might simply refuse to naturalize certain immigrants. It's enough of a puzzle that when the issue came up in the late 19th century, as immigration law was nationalized, the Supreme Court decided that the power came not from the Constitution but from inherent national sovereignty (in rather flagrant disregard of the Tenth Amendment).
My tentative speculation is that the power to admit or not admit foreigners at the border was originally understood as an executive power of the President. In England, it appears that the power was part of the monarch's power over foreign affairs. As I've argued in various places, my view of Article II, Section 1's grant of "executive Power" is that is gives the President the traditional executive foreign affairs powers that were not otherwise given to Congress or shared with the Senate.
If that's right, then Congress' power to make laws relating to immigration arises from its power "To make all Laws which shall be necessary and proper for carrying into execution ... all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof." (I admit, though, that I've not seen this view fully worked out, and I would not go so far as to suggest that the founding generation broadly articulated this view of the immigration power -- only that it appears to be the best textual explanation).