No. It's mandatory for residents of most individual states, but (for example) New Hampshire does not require it of its residents.

Varies from state to state, with almost every state requiring at least liability coverage.

I think the difference is that if a US law maker said "but wont this have a bad effect on the poor?" everybody else in congress bursts out laughing!

Technically insurance isn't mandatory in the US if you are rich enough. At least in Ca if you could show enough assets you can self-insure