Sometime next month, the Supreme Court will decide King v. Burwell, and the conventional wisdom about the stakes in the case appears to have shifted. The case represents a challenge to the core of the Affordable Care Act. The plaintiffs charge that, based on a strict reading of single sentence (actually, four words), federal health-insurance subsidies should be available only in the sixteen states (and the District of Columbia) that set up their own health exchanges, or marketplaces. This means, they argue, that there should be no subsidies for people who now buy insurance on the federal exchange in the other thirty-four states. At the moment, about thirteen million people receive those subsidies.

The people with the most riding on the outcome, of course, are those thirteen million. Without subsidies, it’s likely that most of them will no longer be able to afford their insurance. Until recently, the perception has also been that the Democrats had the largest political stake in the case. After all, the A.C.A. is the signature achievement of the Democratic President. Suddenly, though, and paradoxically, it has come to seem that Obamacare’s Republican opponents are most at risk if the decision goes their way. They have the most to lose by winning. As Jonathan Chait wrote recently, “The chaos their lawsuit would unleash might blow back in a way few Republicans had considered until recently, and now, on the eve of a possible triumph, they find themselves scrambling to contain the damage.” In this view, the peril is especially great for Republicans, because, as Jonathan Cohn recently pointed out, the G.O.P. has failed to propose any kind of plan to address the loss of insurance for so many millions of people.

So that’s the theory: millions will suddenly be uninsured, and will blame Republicans. As Harry Reid, the Democratic leader in the Senate, put it recently, “I don’t think they will [win the case]. If they do, that’s a problem that the Republicans have.”

No, it’s not. If the Obama Administration loses in the Supreme Court, the political pain will fall almost exclusively on the President and his Party. To paraphrase Colin Powell and the Pottery Barn rule, President Obama will have broken health care, so he owns it. To the vast mass of Americans who follow politics casually or not at all, Obamacare and the American system of health care have become virtually synonymous. This may not be exactly right or fair, but it’s a reasonable perception on the part of most people. The scope of the Affordable Care Act is so vast, and its effects so pervasive, that there is scarcely a corner of health care, especially with regard to insurance, that is unaffected by it. So if millions lose insurance, they will hold it against Obamacare, and against Obama. Blaming the President in these circumstances may be unfair, but it’s the way American politics works.

Republicans, of course, will encourage this sentiment. The precise legal claim in King v. Burwell is an esoteric one. It is not based on a claim that Obamacare is unconstitutional. (The Supreme Court upheld the constitutionality of the law three years ago.) Rather, the central assertion by the plaintiffs is that the Obama Administration violated the law itself. In any event, the subtlety of the issue at the heart of the case will surely be lost in its aftermath. The headlines will read, correctly, “Court rules against Obamacare,” and this will be all that matters. The Republicans will argue that the Supreme Court showed that the law was flawed from the start, that the Obama Administration is lawless, that a full repeal of the law is the only appropriate response to the Court’s decision—and that the millions who lose their subsides should blame the sponsor of the law. Watch for references to a “failed Presidency.” There’ll be plenty of them.

Understandably, perhaps, the Administration has courted this kind of reaction. Better than anyone, Administration officials know the scale of the problems that would be created by a loss in the Supreme Court. Advertising this possibility makes sense as a litigation strategy; Obama officials don’t want to make it easy for the Supreme Court to rule against them. In testimony before Congress and elsewhere, Sylvia Burwell, the Secretary of Health and Human Services (and the defendant in the case), said that the Administration has no contingency plan for an adverse ruling in the Supreme Court. But playing chicken with the Justices only works if it works. If the Supreme Court strikes down the subsidies, the Administration will also have to answer for why it didn’t prepare for this possibility.

For many people, the President of the United States is the government of the United States. It’s why he gets the credit and blame for so many things, like the economy, where his influence can be hard to discern. This is particularly true for a subject in which the President has invested so much of his personal and political capital. If the Supreme Court rules against him, the President can blame the Justices or the Republicans or anyone he likes, and he may even be correct. But the buck will stop with him.