The states that have vowed to refuse federal money to cover the poor also have the highest rates of uninsured residents.

Here's a hard truth about the Supreme Court's decision on the Affordable Care Act: The people who are going to suffer most from it are the people who need the help most.

To see why, look at this map from our friends at the Advisory Board (larger version here). One key element of the ACA was to expand Medicaid to cover everyone who wasn't covered by Medicare but made as much as 133 percent of the federal poverty level. That was meant to fill the gap for people who couldn't afford insurance, but were deemed to be poor enough to exempt from the penalty for not holding insurance, even with a subsidy (that penalty is the one that the Court found was a tax). But the justices ruled that the expansion was unconstitutional because it rested upon coercion: The federal government can't force the states to take money and spend it on the expansion.

That means that each state can decide whether it wants to opt into the expansion and receive billions of dollars to expand coverage, with the risk that federal support will fall below the threshold of 90 percent of cost after 2020 (you can find a little more technical detail, but not too much, on this Kaiser Family Foundation fact sheet).

Now, for reasons that range from cost concerns to partisan grandstanding, a variety of governors are rejecting the expansion or threatening to do so. Some say they're concerned that their states will be left with an unmanageable bill in the future; others are rejecting it purely because they disapprove of expanded government involvement in health-care provision.

What this map makes clear is the rather strong correlation between high rates of uninsured residents and states that have rejected or seem likely to reject the Medicaid expansion. You can click on each state to find out where it stands on the law. The five states that have definitively ruled out the expansion -- Texas, Florida, South Carolina, Mississippi, and Louisiana -- all have a population that's 20 percent or higher uninsured. All five also joined the lawsuits against the ACA and have Republican governors and legislatures. Elsewhere, California, which also has a high rate of uninsured (and is run by Democrat Jerry Brown) has announced it will participate in the expansion; Arkansas is leaning toward it (believe it or not, the state has a Democratic governor and legislature). Meanwhile several of the states with the lowest rates of uninsured, such as Minnesota and Vermont, have committed to the expansion. So has Massachusetts, which has among the lowest rates of uninsured in the nation -- thanks to a landmark health-care overhaul led by the state's previous governor, a man named Mitt Romney.

If President Obama is reelected, or if the GOP fails to effectively repeal Obamacare, it will be interesting to see the longer-term results of these choices. Many analysts seem convinced that every state will eventually give in and accept the expansion, finding they can't just leave all that money on the table. But what if they don't? Will there be a gradual but inexorable migration of lower-income citizens to states that expand Medicaid? Will states that refuse the expansion develop a sort of permanent medical underclass? Or will those governments eventually devise some sort of alternative system?

As the old saying goes, only time will tell.