Can Congress require state governors to be confirmed by the U.S. Senate?

Once this week is over, I'll stop looking for more excuses to link to my short Necessary and Proper Clause piece. But I'll seize one final opportunity today. When I was writing the piece, I mentioned on Twitter that I'd "finally found a Charles Black quote I've spent years looking for - it appears zero times on Google or Westlaw." In the highly unlikely event that anybody remembered that and was still wondering about it, here it is. In the course of discussing the need for limiting principles on the scope of federal power, I say:

[E]ven arch-nationalist Charles Black once conceded that the Constitution would not allow Congress to require state governors to be confirmed by the U.S. Senate. [FN]

[FN:] Charles L. Black, Jr., Foreword: The Myth and Reality of Federalism, 9 U. Tol. L. Rev. 615, 616 (1978) ("The subjection of state Governors to confirmation by the United States Senate would have been evidently instrumental to national interest, in the days of the civil rights struggle, but no one even thought of such a step.")

This was Black's best example of the principle that "Congress is not to break in too much upon the internal workings of the state governments as governments." (You can read his whole piece, which is very short, here.)

In any event, I'd originally read this piece sometime in law school (thanks to Marty Lederman), but the piece was sufficiently old and, I guess, obscure that it didn't pop up even in Google or Westlaw. Thanks to this post and the Forum piece, that won't be true anymore.

So when studying the possible "state sovereignty" limits on federal power (which I taught yesterday) don't forget about this possible example.