If you are a legal resident alien, you will be required to obtain the same government-mandated health coverage that US citizens must obtain. However, if you have been here for less than five years, and if your income falls below 133 percent of the federal poverty level, you will not be allowed to enroll in Medicaid. Instead, you will be able to do something low-income US citizens cannot do: obtain highly subsidized insurance (paying a premium, say, of ten cents on the dollar) in a health insurance exchange. If, as we expect, Medicaid insurance is lower quality insurance, you will have access to better insurance than a US citizen with the same income!
If you are an undocumented immigrant you will not be subject to the individual insurance mandates, and you will not be fined if you fail to purchase health insurance. Nor will you be allowed to enroll in Medicaid or buy insurance in the health insurance exchange. However, hospital emergency rooms will not be able to deny you healthcare if you are in need. What makes this surprising is that the most common argument for an individual mandate is that the uninsured should have to contribute to their own healthcare instead of getting it for free in the emergency room. This is why US citizens will be required to pay hefty fines if they do not obtain insurance. If you are here illegally, however, you’re an exception to this rule.
For more about healthcare reform, please see my Independent Institute book, Priceless: Curing the Healthcare.