Justice Thomas’s concurring/dissenting opinion in Zivotofsky warrants a carefuly study, notwithstanding Justice Scalia’s snark. CT raises many points which Nino does not address, or simply brushes away. I break down all of the opinions in detail here. But beyond the issues he raised–as he often does–he noted issues that he would not resolve. This will no doubt provide fodder for future opinions by the Court’s originalist.

First, how should the “Proper” work when Congress tries to exercise a power that belongs to another branch.

That the evidence thus points to a definition of “proper” that protects the separation of powers does not fully ex- plain the way that the “proper” requirement operates when Congress seeks to facilitate the exercise of a power allocated to another branch. I can see two potential mechanisms, either or both of which may accurately reflect the original understanding of the Clause. First, a law could be “improper” if it purports to direct another branch’s exer- cise of its power. See Calabresi & Prakash, The President’s Power to Execute the Laws, 104 Yale L. J. 541, 591 (1994) (“[T]he Clause . . . does [not] allow Congress to tell constitutionally empowered actors how they can imple- ment their exclusive powers”). Second, a law could be “improper” if it takes one of those actions and the branch to which the power is allocated objects to the action. See Prakash & Ramsey 255–256 (“Congress has the general power to legislate in support of the President’s foreign policy goals. But . . . [s]ince it is derivative of the Presi- dent’s power, it must be exercised in coordination with, and not in opposition to, the President”).

I need not resolve that question today, as the application of §214(d) to passports would be improper under either approach.

Second, Justice Thomas raised the question of what the original meaning of “carry into execution” is:

Because §214(d) is not proper, I need not resolve whether such a law could be understood to “carry into execution” the President’s power.

Third, Justice Thomas raised, but didn’t address, what happens when there is a conflict between Congress acting pursuant to an enumerated power and the so-called “residual foreign affairs power.”

As the issue is not presented, I need not decide how a direct conflict between action pursuant to an enumerated power of Congress and action pursuant to the residual foreign affairs power of the President should be resolved.

Fourth, Justice Thomas casts doubt on the modern approach of the “international community” recognizing sovereign states:

Scholars have long debated the extent to which official recognition by the sovereign states that make up the international community is necessary to bring a new “state” into the international community and thereby subject it to international law. Oppenheim §39, at 128–129. Resolving this debate is not necessary to resolve the issue at hand, so I describe the modern view of recognition without endorsing it.

Fifth, Justice Thomas does not reach a question that Justice Scalia addressed–what happens when the President and Congress are each acting pursuant to their powers, and there is a clash. Who wins?

JUSTICE SCALIA’s dissent does at least answer how, in his view, the Constitution would resolve a conflict between the political branches, each acting pursuant to the powers granted them under the Constitution. He believes that congressional power should trump in any such conflict. Post, at 18. I see nothing in the Constitution that clearly mandates that solution to a difficult separation-of-powers question, and I need not opine on it.

There is so much good stuff in Justice Thomas’s and Scalia’s opinions. These intellectual giants rarely duel like this, but this was a battle worthy of the ages.