Aaron Carroll has a blog post entitled A pickle for conservative states refusing the Medicaid expansion.
The background is that Obamacare was designed with the companion Medicaid expansion in mind. However, the Supreme Court threw a wrench into matters when it decided that Obamacare was constitutional but it was unconstitutional to mandate that the states expand Medicaid. Instead, now states have the option of expanding Medicaid (mostly at federal expense) or not.
Obamacare doesn’t provide subsidies for people who were supposed to qualify for Medicaid. So, you have a bit of a doughnut hole occupied by people too well off to qualify for Medicaid under current standards but not so well off that they get beyond the expanded Medicaid eligibility and begin to qualify for health insurance premium subsidies under Obamacare.
On the other hand, *legal* immigrants (and I emphasize legal because that’s so often a sticking point — illegal immigrants are out in the cold regardless) don’t qualify for Medicaid unless they’ve been here for 5 years. Because Congress knew in advance that Medicaid wasn’t going to cover them, they’ll be eligible for subsidies under Obamacare. Conservative states that reject the Medicaid expansion might well see a situation where their poor-but-not-poor-enough citizens get no medical insurance assistance but legal immigrants occupying the same economic space do get assistance by virtue of not being citizens.