Brilliant article in general.
Regarding this specific quote, it is my belief that the US will eventually be the only nation to use nuclear weapons against itself.
America has been a union for over two hundred years, with a brief lapse in the middle. I think it inconceivable that that union will hold for another two hundred years — indeed, if it started to fall apart in late 2020 I would be surprised but not shocked.
And when it does start to crumble, the nukes will likely come out — I pray that I am wrong, but betting against Americans using deadly force is generally a bad idea.