BY BRADLEY JOONDEPH, PROFESSOR, SANTA CLARA LAW

As everyone else following the health care cases recently argued at the Supreme Court, I have no clear idea how the justices are going to rule. But it sure seemed to me—as it did to most observers—that the Court’s five Republican appointees are leaning toward invalidating the Affordable Care Act’s minimum essential coverage provision, the provision that requires most Americans to acquire health insurance by January 2014. This was somewhat surprising.

More surprising, though, was that several of the justices also seemed inclined to strike down the entire ACA, all 2,700 pages of it, on the ground that the minimum coverage provision was inseverable.

This would be extraordinary. It would mark the first time in almost eighty years that the Court invalidated such a significant federal law as exceeding Congress’s enumerated powers. It would also be the first time since the 1930s that the Court used the unconstitutionality of a law’s single provision to strike down a hugely important statute in its entirety.

The justices’ apparent willingness to take such steps suggests they may not fully appreciate the political stakes. A decision to wash away the most significant federal statute in a generation, rendered in the heat of a presidential campaign, could unleash a political firestorm—one that might significantly threaten the stature of the Supreme Court.

Some justices have proclaimed that partisan political pressures have no impact on their decisions; Justices Thomas and Breyer, for instance, have recently stated as much. And it certainly would be troubling if the Court were to take ordinary politics into account in resolving the questions coming before it. The role of the Court, in large measure, is to stand outside politics and render decisions based purely on legal principle.

But this is no ordinary case, and the Court cannot afford to blithely ignore how the Nation’s reaction to its decision might harm its long-term institutional standing. As Alexander Hamilton wrote in The Federalist, the judiciary possesses “neither force nor will, but merely judgment.” And the Court’s ability to serve its assigned role in our constitutional system—as a critical check on the political process—depends on the justices’ capacity to show the Nation that it is exercising principled, reasoned judgment.

In short, the justices must maintain the Nation’s faith that their decisions are grounded in legal principle rather than partisan politics. For if Americans see the Court as no more than another partisan body, the justices’ capacity to persuade persons of diverse ideological hues will be lost. So will, in important respects, our conception of the rule of law.

With respect to the ACA, an ideologically predictable five-to-four decision—especially to invalidate the act in its entirety—runs the risk of creating precisely such an impression. That risk is substantially heightened because of some of the Court’s other recent work—specifically, its five-to-four decisions in Citizens United and Bush v. Gore. The notion that the Court’s decisions could be explained in purely partisan terms would plainly be misguided, but that is beside the point. The impression itself poses serious dangers.

Moreover, the constitutionality of the ACA is only one of several high-profile, highly ideological disputes heading the Court’s way. In the next few years, the justices will also be confronting Arizona’s controversial immigration law (S.B. 1070), the University of Texas’s race-based undergraduate admissions program, a sequel to Citizens United, and the constitutionality of the Voting Rights Act, the Defense of Marriage Act, and California’s Proposition 8. A steady stream of five-to-four decisions along predictable ideological lines—led by a decision to invalidate the ACA—could prove toxic.

This is not just sour grapes from those who substantively disagree with an increasingly conservative Court. Chief Justice Roberts has eloquently voiced the same concern. In his numerous paeans to Chief Justice John Marshall, Roberts has recognized that the Court must attend to its institutional stature with great care. If the justices are careless with the Court’s political capital, Roberts has warned, the Court will “lose its credibility and legitimacy as an institution.”

Indeed, as the Court itself has recognized, its power lies “in its legitimacy, a product of substance and perception that shows itself in the people’s acceptance of the Judiciary as fit to determine what the Nation’s law means and to declare what it demands.” The justices must not just be principled and nonpartisan. They must appear so as well.

Ultimately, the public’s faith in the justices as neutral arbiters of law is essential to the Court’s stature, the independence of the federal judiciary, and even the rule of law. When that faith is diminished, something incredibly precious is lost—something far more important than the outcome of any one case.

I fear that the justices are playing with fire. For the sake of the Court, I sure hope they are careful.

Note: This essay appeared on CNN.com.