Three years ago, in the first Affordable Care Act case before the U.S. Supreme Court, Chief Justice John Roberts invented a legal doctrine that he memorably called the "gun to the head." During oral arguments on Wednesday in the second ACA case, Justice Anthony Kennedy aimed the gun at Roberts.
Roberts originally used the doctrine to gut the ACA's extension of Medicare to unwilling states. Kennedy, by contrast, used it to try to pressure Roberts to save Obamacare by suggesting that Congress couldn't lawfully deny tax subsidies to states that failed to create their own insurance exchanges.
The origin of this metaphoric doctrine goes back to the stealth part of Roberts's first ACA ruling. The big headline back in 2012 was that Roberts joined the court's liberals to uphold the ACA's individual mandate. But in what turned out to be a hugely important part of the decision, Roberts also ruled that Congress couldn't tell the states that if they didn't accept an extension of Medicaid, they would lose all their Medicaid funding. Such a threat, Roberts said, amounted to a gun to the head of the states. It therefore violated the basic structure of federalism.
Under the gun to the head rule, Congress can still bribe states to do things. It can even withhold funding of a limited type, under a still-good precedent in which Congress threatened to withhold 5 percent of states' highway funding if they didn't ban all alcohol sales to people younger than 21. What Congress can't do is, well, motivate the states in a way that five justices would count as a gun to the head.
As a result of the ruling, 22 states have declined to extend Medicaid, vastly reducing the coverage of Obamacare in a random and ethically troubling way.
So how did the gun to the head come up Wednesday? The answer begins with the creative, not to say absurd, reading of the ACA proposed by the challengers to the law. According to the petitioners in King v. Burwell, the statute says that subsidies for health insurance payments can go only to participants in exchanges "established by the state." They claim that this language was meant to specify that if any state fails to establish an exchange, its residents won't qualify for the subsidies.
Because the argument is so implausible, the challengers came up with an even cleverer argument to support it. They suggest that the law was intentionally crafted this way to give states the incentive to create the exchanges -- or lose the subsidies. This, too, seems unlikely, even though an economist involved in shaping the law said something like it after the fact.
Here comes the gun. My Harvard Law School colleague Einer Elhauge, the leading legal authority on the ACA -- and not for nothing, a former Kennedy clerk -- observed some months ago that if the ACA had really intended to threaten the states with removal of subsidies, this threat might well count as a gun to the head, prohibited by Roberts's ruling in the ACA case.
Kennedy clearly heard about this tu quoque (approximate translation: in your face) argument. And he found a great use for it. In questioning the petitioners, he asked whether Congress could have lawfully issued such a threat. He also brought it up with Solicitor General Don Verrilli.
Kennedy's question obviously raises the possibility that he might be willing to decide that the challengers' theory would make the statute unconstitutional. He could then either hold that avoiding unconstitutionality is a reason not to read the law that way, or else actually adopt the challengers' reading and then strike down the provision, making the problem go away. (Probably.)
But that's not what was so important about Kennedy's question. What matters is that Kennedy knows that Roberts, having invented the gun to the head, can't easily abandon the theory now without looking like he's contradicted himself.
And that matters because Kennedy himself probably doesn't want to be the deciding vote saving the ACA. He didn't provide the fifth vote last time. And he almost certainly is about to announce a fundamental right to gay marriage, which is enough of a defection from his conservative origins for one Supreme Court term. Kennedy loves to show that he isn't partisan by deciding cases on both sides of the court's divide. In his ideal world, Roberts, not he, would be the heretic from conservatism to save the ACA again.
Roberts probably doesn't want to break ranks this time. He was almost silent in the oral argument, probably because he doesn't want us to spend the next three months going over his every word. (Kennedy doesn't mind.) But Kennedy has just made it very, very hard for Roberts.
The gun to the head may just turn out to be for this ACA case what the broccoli problem was the last time. Right now John Roberts is probably wishing he'd picked a gentler metaphor.
Noah Feldman, a Bloomberg View columnist, is a professor of constitutional and international law at Harvard.