The ideas of the political theorist Carl Schmitt are enjoying a revival—an unusual point of agreement between elements of the left and right. Schmitt made three striking claims. First, he argued that politics was defined by the dichotomy between friend and enemy. Second, he thought that politics interpenetrated and dominated all spheres of life from aesthetics to religion. Third, he said that sovereignty was located in the institution or person who determined the exception to existing law. Since the executive made that exception at least in times of emergency, the executive tended to be the sovereign.

Even on its face, the revival may seem disturbing because of his personal legacy. Schmitt was initially regarded as the crown prince of Nazi political theorists, even if the Nazis fell out with him before the start of World War II. He also wrote a legal opinion justifying Hitler’s murder of a thousand of his political enemies on the Night of the Long Knives, including former ally Ernst Röhm, chief of the SA (a paramilitary organization associated with the Nazis), and Kurt Von Schleicher, his immediate predecessor as Chancellor of Germany.

Schmitt’s theories have been rightly seen as deeply critical of liberal democracy and inclined toward dictatorship or worse. Nevertheless, they brilliantly illuminate the dangers against which classical liberalism must guard. Indeed, a flourishing liberal society must be the opposite of the one that Schmitt envisions as both necessary and desirable. It must defuse a politics of perpetual enmity, preserve social spheres apart from politics, and constrain executive power, particularly in domestic affairs. In short, Schmitt provides value by being the greatest negative exemplar for liberalism in the modern era. Treating Schmitt as providing a negative credo is more important than ever, because many on both the left and right would take steps to create a world where Schmitt’s dreams and liberalism’s nightmares are more likely to come true. Some academics have irresponsibly cheered them on.

Liberalism vs. Schmittian Principles

One of the earliest efforts of the movement that became liberalism was an attempt to simultaneously oppose two of the principles that Schmitt later outlined as imperative. Liberalism separated religion—the most important social sphere at the time—from politics, and by doing so it tempered the enmity of politics. Religious freedom left belief to the realm of civil society, as the state lost its interest in demanding its citizens affirm a spiritual credo. And because of the state’s relative indifference, citizens had no reason to fight with their fellow citizens over religion. This separation was at first imperfect in an age of established churches. But over time, religious disestablishment followed legally as in the United States and France, or effectively, as in Great Britain where the establishment of the Anglican Church has become as ceremonial as its monarchy.

Meanwhile, the rise of parliamentary democracy was an effort to constrain the executive’s ability to make exceptions to the law. For instance, the Glorious Revolution, a key marker of liberalism’s progress, was sparked, in large part, by James II’s claimed capacity to dispense with laws that he found objectionable. Parliament instead dispensed with James II.

The American Constitution created a structure that pervasively militated against principles that Schmitt later celebrated. First, it established a bicameral legislature with a President who could veto laws, but not issue decrees on his own. As a result, the passage of laws requires substantial social consensus. And social consensus in turn requires compromise. Where citizens are forced to find compromise, they must look for what they have in common with their political rivals, and thus model a form of politics the very opposite of a friend-enemy distinction.

The Constitution also limited the federal government’s power by providing a Bill of Rights. This structure reduced the danger that politics would penetrate all spheres of society. Constitutional amendments that could upend this carefully calibrated system and leave much of social life more open to politics require even greater social consensus than the ordinary legislative process.

To be sure, under the Constitution of 1789, the states had very substantial powers that were not limited by the federal Constitution. But the Fourteenth Amendment placed limits on those powers, and in any event, citizens can leave their states relatively easily—a right that is also protected by the Constitution. The possibility of exit restrains the worst excesses of a politics of friends and enemies, because there is less reason to fight if one can flee.

The Constitution also consciously limits executive power. The requirement to “Take Care that Laws be faithfully executed” reflects the Glorious Revolution’s settlement against any executive dispensing power. The President is to execute not make exceptions to the law. But the Constitution goes beyond that settlement to further reduce the ability of the President to act alone as sovereign. The British monarch could declare war and make appointments and treaties unilaterally. Under the American constitution that power is shared—with the entire Congress in the case of war, and with the Senate in the case of treaties and appointments. The Constitution represents another step toward constraining unchecked executive power beyond that accomplished in the Glorious Revolution. That development also reduces the danger that enmity will dominate politics, because more of governance will require resort to the legislature where compromise is necessary rather than reflect executive fiat.

And that Constitution has in turn generated a distinctively American political culture—one that has in the past rewarded bipartisanship and dealmaking. In one of the greatest lines in any Inaugural Address, Jefferson said, “We are all Federalists, we are all Republicans,” rejecting the friend-enemy dichotomy. His greatest successors have followed him in this. Schmitt believes that this culture is ultimately unsustainable. In a sense, the most important social question we face is whether we can prove him wrong by sustaining our liberal constitution and the social culture it helps generate.

The Risks of a Schmittian Revival

It is worth recalling how our constitutional order is a strategy for negating or at least constraining the three principles favored by Schmitt, because of the many proposals to dissolve constitutional constraints and politicize law. For instance, the recent Democratic proposals to pack the Supreme Court will undermine the amendment process that requires social consensus to change the Constitution. And packing will not just happen once: after one packing, whenever a single party controls the President and Congress, the Court is likely to be packed again. And because of that new structure of appointment, judging will itself become more rawly political, being drawn into the circle of friend and enemy.

While this effort at weakening the restraints that temper enmity in politics comes from the left, the right has been too willing to erode constitutional constraints, even if less dangerously. The Constitution requires a quasi-legal finding of “High Crime and or misdemeanor” as a basis for impeachment, rejecting maladministration as a sufficient justification. Our current Homeland Security is indeed hapless, but it is much harder to find any High Crime or Misdemeanor in his actions. The House has not impeached executive branch officials for good faith interpretations of the law in the past, even if it disagreed with them. Yet the Republican House just impeached him. We can be sure that the next time that President is a Republican, a Democratic House will retaliate by impeaching one of his cabinet members on similar grounds, creating a cycle in which policy and administrative disputes become more intense and bitter, leading to greater political enmity.

Most disturbingly for the long term, academics almost as prominent in their day as Schmitt was in his are making proposals to junk our Constitution altogether by unconstitutional means. For instance, Ryan Doerfler, a Professor at Harvard Law School, and Samuel Moyn, a professor at Yale Law School, have argued that the progressives need to “reclaim America from Constitutionalism.” They openly advocate the national legislature breaking clear constitutional rules. For instance, they think that the Senate might be made into a council of revision without the power to obstruct laws passed by the House of Representatives. They worry too that the Bill of Rights orients us toward the past and does not focus on “what the present and the future stand for and from those who live now.”

Dissolving the Constitution through transient majorities is the way to create a politics of friend and enemy. A unicameral legislature unconstrained by the Bill of Rights would turn up the temperature of politics, making every election more momentous and divisive. That is not a bug in their proposal but a feature. They want a “continual reinvention of our society”—which puts everyone’s lives at the mercy of politics. It would also make it easier for the sphere of politics to dominate others, like religion, the market, and our culture. Unsurprisingly, given that its suggestions would lead to a politics dominated by enmity, the professors’ essay contains bellicose rhetoric about “fighting” and “weaponry.” While these proposals are not likely to be adopted anytime soon, they show where left-wing professors would like to lead the next generation.

Sadly, however, the enthusiasm for turning politics into an existential struggle dominated by friend and enemy is not unique to the left. As David Corey has noted, “Many young (and not-so-young) people on the Right today believe they know the answer to such questions. Their answer is to take the idea of culture ‘war’ much more seriously: to treat politics like actual war, a winner-take-all contest where ‘friends’ and ‘enemies’ vie over the right to exist.”

Liberalism is more embattled in the United States than it has been for decades. Schmit’s theories show that attacks today are potentially deadly because they do focus on its fault lines. Liberalism has created institutions and a culture that constrain politics from dominating social life, which encourages compromise where citizens must consider what they have in common, and that restrain the executive from ruling by fiat. Each of these efforts is interconnected, allowing individuals to lead a flourishing life of their own choosing apart from politics. The more these liberal orders fail to maintain themselves, the more people will come to the Schmittian belief that liberal constitutionalism is a fairy tale and that politics must necessarily be generated by the distinction between friend and enemy. But the memory of the consequences of Schmitt’s theories should be to us a fire bell in the night.