[MACVSOG68]

And except on the frontier, there wasn't that much of a day-to-day need for a militia even in 1789

Nonetheless, Washington put his army together from state (colonial) militias, and the state militias continued to exist on into the new nation. Even in the War of 1812, state militias were called up and some refused.

But now as well as then, there is a need for every state to have the capability of forming one, so that it can be defended against usurpations of power.

I seriously doubt after the Civil War, any state is going to form some sort of militia over and above the national guard to protect itself against "usurpations of power", whatever that may mean to you.

[inquest]

Nonetheless, Washington put his army together from state (colonial) militias

There was no federal government at the time to give him a standing army. But you make my point: When fighting against your own army when it's trying to take away your freedom (as Washington was doing), you need militias. That was the whole point about it "being necessary to the security of a free state".