When the D.C. Circuit Court ruled this week that the Affordable Care Act unambiguously prohibits subsidizing health plans on federally-run exchanges, raising the possibility that the Supreme Court might gut the law on second pass, I argued that an adverse ruling in Halbig v. Burwell would actually be bad politics for Republicans: that the pressures such a ruling would create might be enough to divide Republicans and force Republican governors and members of Congress to address the resulting inequities.

The good news is, we have a pretty good, recent, real world example of how these pressures work. And it bodes pretty well for supporters of the Affordable Care Act.

It's possible that after an adverse ruling in Halbig, the American health care system would reach quasi-stable equilibrium. Bluer states would reap all of the ACA's benefits, redder states would enjoy none. I examined that possibility here. New York magazine's Annie Lowrey drew a comparison between an adverse Halbig ruling and the Supreme Court's decision to make the ACA's Medicaid expansion optional. As a result of that ruling, nearly two dozen states have declined to expand Medicaid leaving millions of low-income Americans stuck in the coverage gap.

But I don't think Medicaid expansion is the proper analogy.

The Republicans who opted out of the Medicaid expansion had Obamacare's implementation timeline on their side. At the time of the ruling in 2012, zero people in the country were eligible for expanded Medicaid, because the Medicaid expansion wasn't effective until January 1, 2014. Republican governors could opt out without making anyone's lives worse. Or rather, they could make people's lives worse without taking anything away from them.