system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:If a single state, like Colorado, passes a single-payer health insurance program, what's to prevent people who don't pay taxes from rushing the state?

I've read that Colorado is debating implementing a single payer state health insurance system.  My dad, who is in his 70s, and doesn't work any more, is talking about moving there because his health coverage is garbage.  Would the new health insurance not cover people like my dad who only collect Social Security, or do they have a plan to prevent the system from collapsing?  What's to prevent millions of non-working seniors and other disabled people from moving to Colorado for the "free" health insurance?
gpt
I do not understand why your father does not have Medicare which is not garbage. Colorado may establish a residency requirement stiff enough to discourage this mass movement.

Colorado will not be able to forbid immigration. But they could establish a one year residency requirement for the new program.