If the Supreme Court strikes down Obamacare later this month, the ruling will be based on the inability of five or more justices to reconcile the law’s individual mandate with the Constitution. These justices will have reached the conclusion that the enumerated powers of the federal government do not include the authority to force individuals to buy health insurance so that Congress can then regulate that activity via the interstate commerce clause. Such a decision will be incredibly humiliating for the President, but it will doubtless provide a certain amount of schadenfreude to his Secretary of State. Hillary Clinton, you will recall, was subjected to relentless attacks by Obama during the 2008 Democrat primaries because her plan to reform health care included such a mandate.

In those long-forgotten primary battles, Obama repeatedly touted his opposition to an individual mandate as one of the major distinctions between his “reform” plan and that of his main rival for the nomination. During the 2008 Democrat debates he routinely upbraided Clinton for advocating a policy that he said was fundamentally unfair: “[T]he reason people don’t have health insurance isn’t because they don’t want it, it’s because they can’t afford it.” To drive home his point, he frequently employed the following mordant analogy: “If a mandate was the solution, we can try to solve homelessness by mandating everybody to buy a house.” Such heresy produced denunciations from a variety of progressives, including Paul Krugman, who accused Obama of “echoing right-wing talking points.”

Such criticism notwithstanding, Obama’s ostensible aversion to government-imposed mandates was shared by most voters. Moreover, Obama’s stated position was correct on the merits. As had already been demonstrated in Massachusetts, insurance mandates don’t fix the “free rider” problem they are purportedly meant to solve. Uncompensated care had continued to increase in the Bay State despite the imposition of just such a mandate on its citizens in 2006. Nonetheless, when the health “reform” bills began taking shape in the Democrat-controlled Congress in 2009, the mandate again reared its ugly head, and the new President’s opposition began to evaporate. In June of 2009 the New York Times reported that Obama had become “receptive to Congressional proposals that would require Americans to have health insurance.”

In the end, of course, the health care legislation that President Obama signed into law included precisely the kind of individual mandate that he had vehemently denounced while running for president. In addition to revealing Obama as just another cynical and unprincipled Beltway politician, this brazen flip-flop may well have preordained Obamacare’s ultimate demise. Florida v. HHS, which challenged Obamacare based on the claim that the individual mandate is unconstitutional, was filed in U.S. District Court for the Northern District of Florida on the same day the law was signed. This lawsuit was predictably denounced by the White House as a frivolous publicity stunt, but it was taken quite seriously by U.S. District Judge Roger Vinson, who struck down the law in its entirety in January, 2011.

This ruling earned Judge Vinson a tsunami of abuse from left-leaning law professors, pundits, and politicians, while the Department of Justice (DOJ) attempted to have his ruling overturned in the Eleventh Circuit Court of Appeals. But that court also ruled the mandate unconstitutional. Unlike Judge Vinson, however, the three-judge panel representing the Eleventh Circuit declined to strike down the entire law. This conflict between the rulings of the district and appeals courts set the Obamacare challenge on a direct path to the Supreme Court. And, when it finally reached that exalted tribunal, it became obvious why the DOJ had sought so long to delay that day of reckoning. The Obama administration fared so poorly in March’s oral arguments that the most common term used to describe its case in the media was “train wreck.”

Predictably, it was the mandate upon which the DOJ’s argument came a cropper. When it came time for Solicitor General Donald Verrilli to defend it before the assembled justices, he fell on his face. As one progressive publication phrased it, “Verrilli delivered a rambling, apprehensive legal defense of liberalism’s biggest domestic accomplishment since the 1960s.” But the hapless Solicitor General wasn’t defending “liberalism’s biggest domestic accomplishment” that day. He was attempting to defend the law’s individual insurance mandate, a provision requiring Americans to buy a certain product from certain private corporations even if we have no desire to do so. Who wouldn’t have trouble defending a coercive federal decree that even the president for whom he works had denounced dozens of times as unfair?

If, after his election to the presidency, Obama had held fast to his oft-expressed opposition to the individual mandate, it probably would have been more difficult to get “reform” passed. But most presidents finding themselves in such a situation would have reached across the aisle and offered some compromise that would have produced enough votes to get the bill across the finish line with a modicum of bipartisan support. However, as Maureen Down wrote over the weekend, Obama considers such efforts beneath his dignity: “As president, Obama has never felt the need to explain or sell his signature pieces of legislation.” Rather than compromise, he participated in a wide variety of backroom deals and executed an egregious flip-flop on the individual insurance mandate.

That crucial reversal is what landed Obamacare in the Supreme Court. If the law contained no insurance mandate, the number of challenges to the law would have been far fewer and the chances that any would have reached the Supreme Court would have been far lower. But Obama doesn’t like to compromise with people he considers the enemy. As he tersely stated when he rejected good faith Republican proposals made during the 2009 “negotiations” concerning his failed stimulus package, “I won.” He has, however, been more than willing to compromise many of his alleged principles. And his willingness to do so in the case of the mandate may well have doomed his “signature domestic achievement.”