President-elect Trump has announced that he will nominate General James Mattis to serve as Secretary of Defense. This “legendary” general is talented and well-regarded, but his nomination may prompt a problem. Mattis, you see, “retired from the Marine Corps in 2013,” but federal statutory law states that “[a] person may not be appointed as Secretary of Defense within seven years after relief from active duty as a commissioned officer of a regular component of an armed force.” Some in Congress may be reluctant to waive that bar.

But is this statutory bar constitutional? Perhaps not. For instance, Shannen Coffin at National Review submits that:

Congress has no role in deciding whom the president can nominate. Congress does have a role in the appointment of those officers, but that is limited to the Senate’s “advise and consent” role. In both the nomination and appointment process, the ultimate power lies with the President. Congress cannot limit who the president chooses to appoint as an executive officer. The Senate can withhold consent, but that is as far as they can go in preventing the president’s appointment. …. [I]f 51 Senators simply chose to ignore the statute and vote for Mattis without observing the statutory ban, there’s every reason to think that their actions would be legal under the [C]onstitution.

He followed up this post with additional analysis.

In response, Andrew McCarthy (also at National Review) argues that the statutory bar is indeed constitutional:

Nothing in the Constitution requires that there be such an office. Indeed, nothing in the Constitution mandates that Congress establish federal armed forces at all, although the Constitution expressly permits Congress to do so (art. I, sec. 8, secs. 12-14). Since Congress did not have to provide for a Secretary of Defense at all, and could theoretically restructure the military in a way that eliminated the position (which didn’t exist for the first 160 years of constitutional governance), it would be odd if Congress were without power to mandate qualifications for the office.

I am not an expert by any means on the Appointments Clause. But I am aware of scholarship touching on this question. In particular, Hanah Metchis Volokh published this article in 2008: “The Two Appointments Clause: Statutory Qualifications for Federal Officers.” Here is the heart of her analysis:

I will argue that statutory requirements are unconstitutional for all appointments that require the advice and consent of the Senate. Despite a long history of statutory qualifications, the text and structure of the Appointments Clause reveal that Congress is not authorized to limit who may hold office in this way. Confirmation by the Senate, not statutory restrictions from the full Congress, is the process the Founders designed to ensure responsible appointments of officers. Adding statutory qualifications to the mix can bar excellent people from holding office and can also reduce the accountability of the President and Senate when they make bad choices.

Not all statutory qualifications for officeholders are unconstitutional, however. Appointment of inferior officers does not require the advice and consent of the Senate. When creating an inferior office by statute, Congress can choose to keep the appointment within the default advise and consent process, or it can vest the appointment “in the President alone, in the Courts of Law, or in the Heads of Departments.” If Congress chooses to vest the appointment in one of these appointing authorities, it may also create specific qualifications for the officeholder in the statute. Because Senate confirmation is not available to provide the check on power in these appointments, a similar check can be provided by constraining the appointer’s discretion through statutory requirements. This result is consistent with the text and structure of the Appointments Clause.

She also notes that both President George W. Bush and President Clinton argued that statutory qualifications can be unconstitutional. (Here also is a student note that touches on the question.)

Under this argument, General Mattis would not need a waiver since the Secretary of Defense (surly a principal officer under the Constitution) requires Senate confirmation.

On the other hand, in 1789, Congress enacted a statute declaring that “there shall . . . be appointed a meet person, learned in the law, to act as attorney-general for the United States.” The fact that Congress imposed a qualification on the Attorney General (also a principal officer) more than 200 years ago is some evidence that such statutory bars are constitutional. (There is more about this history in the linked articles.)

Like I said, I have no idea who is right on this question; indeed, I have spent just a few minutes even thinking about it. And the issue will probably be moot anyway because presumably Congress will grant the waiver for General Mattis. But the question is interesting and these articles are a good place to start if you want to begin piecing together the constitutional puzzle.