WASHINGTON, DC - MARCH 27: Sisters and Tea Party members of Atlanta, Georgia, Judy Burel (L) and Janis Haddon (R), protest the Obamacare in front of the U.S. Supreme Court. (Alex Wong/GETTY IMAGES)

President Obama’s plan to transform the U.S. health-care market is once again in trouble. This time, two Republican-appointed judges on a federal appeals court have invalidated a key portion of the program.

In other words, the U.S. constitutional system is functioning normally.

That’s not to say that the majority of a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit correctly struck down the issuance of tax credits through the federal health insurance exchanges in 36 states — though it is true, as the judges said, that the law only speaks of “Exchanges established by the State.”

There is a strong argument that ambiguities in the statute should be resolved in favor of the Internal Revenue Service’s interpretation, given the law’s manifest purpose to expand coverage, as a Democratic-appointed dissenter on the D.C. Circuit (as well as a unanimous Richmond-based federal appeals court) concluded.

Rather, the very existence of this case, Halbig v. Burwell, illustrates basic aspects of the U.S. political system about which progressives are in deep denial: Specifically, the Constitution is designed to inhibit comprehensive national legislation like Obamacare.

Why did the Framers create a federal government of limited and enumerated powers — leaving everything else to the states and “the people”? Why did they provide for so many veto points and counter-majoritarian institutions — frequent House elections, the Senate, federal courts?

These were checks against the rise of what James Madison called “an unjust and interested majority” that might enact its “rage for paper money, for an abolition of debts, for an equal division of property, or for any other improper or wicked project.” Madison understood that misguided “projects” could spring from good intentions as well as evil ones. And the Constitution has protected us from many of them over the years.

To be sure, its conservative tilt has not always served the country well. Among the many national problems that festered absent national decision-making, slavery was the worst. Messed-up health care is another.

Conversely, the Constitution, as amended and as capaciously interpreted by the Supreme Court, accommodated many necessary changes, incremental and otherwise, that the Framers did not foresee or mistakenly abhorred — like the paper money in your pocket.

Social-change legislation on a grand scale, however, of the kind progressives routinely promise, has come in only a few brief, extraordinary periods when reformers managed to dominate Washington: Reconstruction, the early New Deal, the Great Society.

Progressives thought the 2008 election of Barack Obama, along with a Democratic House and Senate, presented another such opportunity.

They overestimated their purchase on a polarized electorate and underestimated the inevitable counter-reaction. By its nature, comprehensive legislation upsets the status quo and therefore mobilizes those with a stake in it.

The backlash arrived in the first year of Obama’s presidency, in reaction to the stimulus bill, a cap-and-trade proposal and, of course, Obamacare. It flooded every inch of political space the Constitution created, culminating in raucous anti-Obamacare assemblies and the victory of Republican Scott Brown in the January 2010 Massachusetts special Senate election.

Their filibuster-proof Senate majority gone, Obama and Democratic congressional leaders opted to pass Obamacare with the help of a maneuver known as “reconciliation.” The risk of a Republican Senate filibuster ruled out the usual House-Senate conference, which might have fixed the ambiguity about state and federal exchanges.

Hence the IRS’s interpretive patch. And hence Halbig, which, like previous Obamacare litigation, shows the power of the courts, in combination with the states — 36 of which opted out of the Obamacare exchanges, and 24 of which haven’t expanded Medicaid — to complicate plans hatched in Washington.

Republican opposition to Obamacare may be hypocritical, irrational and opportunistic — especially GOP opposition to the exchanges, which the party previously favored in various forms. And, yes, the modern filibuster takes counter-majoritarianism to an extreme even the Framers probably didn’t contemplate.

But the Constitution lets the Senate write its own rules. As for GOP resistance, it’s shocking that progressives are shocked by it. Did they expect the opposition to facilitate a law Democrats advertised as their key to a permanent political majority?

Everything might have been different if Democrats and Republicans had operated in a spirit of compromise, the Framers’ hoped-for political solvent.

On the health-care law, however, only Chief Justice John G. Roberts Jr. has played against partisan type; in 2012, he cast a deciding vote to uphold it, much to the fury of his fellow conservatives. Democrats, for their part, pocketed the win and resumed loudly reviling the chief when he ruled against them on other issues.

Now Halbig may be headed to the Supreme Court, where the progressive vision of universal health care could hinge on Roberts’s vote once again.

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