Something worth protesting, right?
I mean, there can't be anything in The Constitution about such a monstrous thing! And if there were, it would surely ban the government from targeting Americans. Right?
It's Article 1, Section 8, Clause 15:
To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;It's called the Militia Clause, and it's defended rather well in the Federalist Papers (No. 29). Senator Paul might also want to cast his mind back to a significant bit of American history - The Civil War. That involved American troops killing Americans.
The Obama Administration is simply ensuring that it doesn't, can't, restrict future Presidents. It's not deriving some new doctrine, principle or power - it was first used by George Washington in the Whiskey Rebellion. And as all these things go, there's more to the principle than immediately appears. Senator Paul probably doesn't care about that; his is not a Constitution that lives in reality, but a malleable and proscriptive one that lives in his mind.