A select militia is no militia at all. It defeats to core purpose of a militia. And it isn’t deployable by the President. But it is by Congress (then under Exec leadership). Read the Federalist Papers/Antifederalists Papers. Throw Blackstone and Story in there too.
To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions; -Article 1 Sec 8
The President shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States; - Article 2 Sec 2