People are, rightly, upset about all that's going wrong with the president's health-care law. But something unexpected is going very, very right.

(Mark Wilson / GETTY IMAGES)

The background here is that before the rollout of the Affordable Care Act there were a lot of people  eligible for Medicaid who simply didn't know it. This "take-up rate" -- wonk-speak for the percentage of people eligible for the program who sign up for it -- varies widely from state to state, with some states as low as 36 percent and others as high as 81 percent.

The publicity around the new health-care law has led a lot of those people to inquire about whether they're eligible for health insurance -- and they're finding out that they are. The clearest example of this is in the red states that aren't participating in the law's Medicaid expansion: There, 91,000 people have tried to sign up for health insurance and learned, in the process, that they are already eligible for Medicaid coverage.

The effect is also present in the blue states. The Kaiser Family Foundation reports that of the 70,000 people who've enrolled in Medicaid in Washington State, 30,000 were eligible before the new law took effect -- they just didn't know it.

The result is that while the expansion of health-care coverage still isn't working nearly as well as it needs to be, it's actually making preexisting coverage expansions work better than they ever have.