I'm not sure the Constitution can delegate anything to the States. The Constitution is a grant of a set of enumerated powers to the national government, by the States. They didn't need to delegate to themselves what was theirs to start with.
The Congress shall have Power ... To provide for organizing, arming, and disciplining, the Militia, and for governing such Part of them as may be employed in the Service of the United States, reserving to the States respectively, the Appointment of the Officers, and the Authority of training the Militia according to the discipline prescribed by Congress;Make of that what you will.