being a member of the party in the same way elsewhere you’d be a fee-paying member of Labour, or the Greens, or Die Linke

There's no such thing. "Registered Democrat" is pretty much being a member of the party. The money comes from corporate and [m/b]illionaire donors.

Why are the Dems so useless again? Who (or what?) is exactly is running the country again? Capital. of course.