If all goes as planned, the Affordable Care Act will extend insurance coverage to 30 million Americans in the course of a decade. It will also leave 30 million Americans uninsured. One quarter of that population will be undocumented immigrants.
Non-citizens living in the United States have, for decades, had significantly lower rates of health insurance coverage. The Congressional Research Service estimates nearly half of non-citizen residents of the United States lack insurance coverage.
The health-care law does offer new coverage options for legal immigrants. They, like American citizens, are eligible for subsidized health insurance coverage if they earn less than 400 percent of the poverty line ($44,680 for an individual).
Legal immigrants can also qualify for Medicaid coverage after five years of legal residence in the United States. This was true prior to the Affordable Care Act, but will likely become more meaningful when many states expand their Medicaid programs up to 133 percent of the federal poverty line.
Legal immigrants will also be subject to the mandated purchase of health insurance coverage at the start of next year.
For undocumented workers, the post-Obamacare landscape is markedly different. Undocumented workers are barred from federal subsidies and also exempt from the individual mandate. There might be some residual benefits; the ban on pre-existing conditions, for example, would extend to all American residents. The lion's share of the law's coverage expansion, however, would stay out of reach.
Due to these constraints, the Congressional Budget Office has estimated about 7 to 8 million undocumented immigrants will remain uninsured under the Affordable Care Act.
If immigration reform were to shrink the undocumented population - or eliminate it altogether - new paths to coverage would open up - and that uninsured population would likely shrink. The Congressional Research Service estimates that 80 percent (17.5 million people) of non-citizens would, due to their income level, qualify for some part of the insurance expansion.
Keep in mind, CRS data does not break out documented and undocumented non-citizens; this graph includes both groups. Still, it's a helpful guide to think about the income levels of this population.
The yellow chunk of the pie chart shows everyone earning less than 133 percent of the poverty line. These are people who would qualify for the Medicaid expansion, although would be subject to a five-year waiting period (during that time, however, they would have the option to buy insurance using federal subsidies).
The blue slice, 46.3 percent of the non-citizen population, would qualify for federal subsidies to purchase private insurance coverage. The last part of the population, represented in red, would not qualify for assistance - not due to their immigration status, but because of their higher income. They would still, however, have access to their state health insurance exchange. Right now, undocumented immigrants are specifically barred from buying coverage there (as part of the purchasing process, Homeland Security will verify citizenship status).
Stretching the health law's insurance expansion would, unsurprisingly, come at a price: Covering more people means spending more money. Medicaid spent an average of $7,434 per patient in 2011. It would be a necessary, and perhaps surprising, side-effect of changing the way immigration works.