US National ID Card
This was first created in December 2004’s Intelligence bill, loosely called the Patriot II act because it snuck in provisions like this without the Representatives knowing it. The deal is basically a no-option offer to the states: either you issue all your state citizens with nationally approved cards, or all federal employees are instructed to reject access. As ‘public’ transport (including flying) falls under federal rules now, that means … no travel, so it’s a pretty big stick.
Ian Grigg got to this before me. Lefty freaks like Gun Owners of America are opposed.