On Monday August 18, Affordable Care Act opponents’ legal champion, Michael Carvin, filed a little-noticed brief with the District of Columbia Circuit Court of Appeals, forbiddingly entitled “Opposition to Petition for Rehearing En Banc,” in the ongoing litigation challenging the legality of tax credits and subsidies for health insurance purchasers on federally operated exchanges. The D.C. Circuit’s decision on this procedural issue could play an outsized role in deciding the ultimate fate of the litigation, and determine whether those exchanges—currently covering several million Americans in 36 states—will continue their currently impressive growth, or collapse outright.

On July 22, a unanimous three-judge panel of the Fourth Circuit Court of Appeals in Richmond rejected the challenges and upheld the availability of premium assistance on all exchanges, whether state or federally run. However, on the same day, Carvin secured endorsement of his challenge from a D.C. Circuit panel split 2-1—with a Bush I appointee and a Bush II appointee voting to bar the credits and subsidies in federal exchange states, and a dissenting Carter appointee dismissing the lawsuit as a “not-so-veiled attempt to gut” the ACA.

On August 1, the Justice Department requested that all eleven active D.C. Circuit judges rehear the case “en banc” (legalese for “as a group”). Carvin fired back last Monday. Carvin’s brief exposes his and his allies’ fear that the resolution of their several last-ditch lawsuits to “drive a stake through the heart of Obamacare,” likely turns on whether they can persuade the DC Circuit to reject the Justice Department’s request. Revealingly, the brief observes that “if this Court denies rehearing, there is no doubt” that the Supreme Court will immediately take the case, by granting his pending petition for immediate high court review of last month’s contrary Fourth Circuit Court of Appeals decision. Of course, the unspoken obverse of Carvin’s forecast is that, if the D.C. Circuit grants “en banc” review, the Supreme Court may well opt not to preempt the DC Circuit’s review. If, as expected by many observers, the full D.C. Circuit overturns Carvin’s 2-1 July 22 victory, that would in turn eliminate any split between the two circuits, severely weakening Carvin’s argument to get the Supreme Court to take the case. That is precisely what Carvin and his allies dread. If the Supreme Court decides to wait and see how the DC Circuit rules, ACA opponents could well see this as a demoralizing sign of distaste, on the part of one or more of the conservative justices, for taking up another legally dubious attempt to cripple Obamacare, now that millions of Americans actually have health insurance because of the law.

On the face of the applicable rules, Carvin’s prospects for persuading the D.C. Circuit judges to sideline themselves would seem iffy at best. These rules spell out that a reason for granting en banc requests is that the case “presents a question of exceptional importance,” and goes further to prescribe one circumstance that ipso facto presents such a question—“if the initial panel decision conflicts with decisions of other circuits.” Carvin did not so much as cite this provision. Instead, he warned, horrific real-world consequences will flow, from granting the rehearing petition. It cited a conjecture by the New York Times’ Robert Pear, that “the contradictory rulings … inject uncertainty, confusion, and turmoil into health insurance markets,” and claimed that millions of individuals in federal exchange states could not only lose insurance, but that “they may be incurring thousands of dollars of debt to the Treasury, since the ACA contemplates a clawback of improperly paid subsidies.”

In fact, insurance market jitters have not materialized, and Carvin’s “clawback” specter is wrong, as a matter of law, as health law expert Timothy Jost has noted. But more important, a do-over by the full D.C. Circuit will do, quite literally, nothing to exacerbate these and other horribles paraded in Carvin’s brief. Carvin fears that the Supreme Court may well stay its hand, if the case is reheard at the appellate level. But the choice will still be up to that Court. If the justices consider it urgent to impose their take, rather than wait to see if the elimination of a circuit split vitiates the necessity for intervention, the lower court’s en banc deliberations certainly won’t stop them. On the contrary, a decision not to rehear the case will wrest the wait-and-see option from the high court, increasing pressure for it to intervene before the appellate process has run its course. In effect, Carvin seeks to bluff the D.C. Circuit into turning the usual roles of the courts of appeals and the Supreme Court upside down.