That’s because Medicaid is not one program but 50. Unlike Medicare, which covers all Americans 65 and older, Medicaid is administered at the state level. Individual states have a huge amount of control when it comes to deciding who qualifies and what care they can receive. While the federal government sets some requirements, the decision-making power of individual states means there are some places where it’s worse to be sick than others.

In California, for instance, a single person making $10,000 a year qualifies for that state’s Medicaid, but if that same person lives in Texas, they don’t. Some states cover eyeglasses, hearing aides, and hospice care. Others don’t.

For some Medicaid recipients, this state-by-state variation can be a matter of life or death — not just in emergency situations but in the long-term benefit of providing people with routine medical care that catches problems early.

Recent Republican efforts to repeal the Affordable Care Act threatened Medicaid from a variety of angles, like making eligibility even narrower or changing the way state programs are reimbursed by the federal government.

At the same time, Medicaid itself may be the reason those larger efforts failed in the first place. And now that Republican plans have stalled, the potential to provide health care for millions more people sits on the desks of governors, not senators.

Put simply, Medicaid works, even if it works better in some states than others. But how did we arrive at this complicated system in the first place? Many countries around the world offer single-payer health care or tightly regulate private insurers to make sure every person can get coverage for what they need. So why didn’t that system catch on in the US? Watch the video above to find out.