Opinion of Thomas, J.
Scalia's final piece of historical support—the increased congressional regulation of passports following the Civil War—is perhaps more on point from an institutional perspective, but still does not resolve the issue. Those regulations were, as I have already described, narrow in scope and continued to leave primary regulation of the content of passports to the President. To draw an inference from these “late-arising historical practices that are ambiguous at best”—and that might conflict with the original meaning of the “executive Power” and the “proper” requirement in the Necessary and Proper Clause—is a dubious way to undertake constitutional analysis. See Noel Canning, 573 U. S., at 570 (Scalia, J., concurring in judgment).
Even more dubious, however, is the cursory treatment of the Necessary and Proper Clause in Justice Scalia's dissent. He asserts that, in acting pursuant to that Clause, “Congress . . . may not transcend boundaries upon legislative authority stated or implied elsewhere in the Constitution.” Post, at 70. But he offers no explanation for what those implied limits might be or how they would operate. Does he, for example, agree that the word “proper” requires Congress to act in a manner “ `consistent with principles of separation of powers, principles of federalism, and individual rights' ”? Supra, at 48 (quoting Lawson & Grainger, 43 Duke L. J., at 297). If so, then why does he find that requirement satisfied in this case? Is it because he views the President as having no constitutional authority to act in this area? Or is it because he views Congress' directive to the President as consistent with the separation of powers, irrespective of the President's authority? If the latter, is that because he perceives no separation-of-powers limitations on Congress when it acts to carry into execution one of its enumerated powers, as opposed to the enumerated powers of another branch? And if that is the case, what textual, structural, or historical evidence exists for that interpretation? Justice Scalia's dissent raises more questions than it answers.
