In the wake of Islamic State’s murderous blitzkrieg, Barack Obama has vowed the United States will fight to destroy the militant group ‘wherever they are.’ Holding off IS’s advance might require raw military might, but understanding their genesis and rapid rise takes us back to the writings of an often reviled German jurist, Carl Schmitt. After admirably defending the beleaguered Weimar Republic in the 1920s, Schmitt irreparably muddied his record by joining the Nazi party in 1933 and launching anti-Semitic attacks. Nevertheless, he remains part of the pantheon of German intellectual icons for his devastating demolition of the liberal democratic fantasy that popular sovereignty and the protection of individual rights and freedoms always go hand-in-hand.

Schmitt could not have foreseen how Iraq’s sectarian schisms would produce a groundswell of Sunni support for IS’s genocidal agenda of beheading infidels and apostates. Yet in The Crisis of Parliamentary Democracy, Schmitt provides us with the theoretical framework to understand the apparently perverse union of a quasi-democratic uprising with brutal totalitarianism. Schmitt argued that the governing principles of liberalism and democracy are so vastly different that these political systems are actually often irreconcilable. The ever-present possibility of the people willing that certain individuals be stripped of their rights and freedoms means that liberal democracies must decide whether they are at base liberal or democratic: when the people are illiberal, will their popular preferences be legislated, or will the imperative of protecting individual liberty constrain their choice?

This clarity of thought would have left Schmitt unsurprised by the rising fortunes of Islamist militants in Libya, the enduring rule of Hamas on the West Bank, and the successes of IS. By seeking to enforce faith as the foundation of political, social and even economic life, Islamism in all its forms is inherently illiberal. Yet it is not necessarily at odds with democratic rule. Democracy is merely what Schmitt called an ‘organisational form’; stipulating the will of the people should be sovereign. The victories of various strains of Islamism, including puritanical movements with vicious vendettas against minorities, are therefore not necessarily anti-democratic. In fact, as the international community is realising, these Islamist revivals have been fuelled by widespread appetite for political systems that are not just unapologetically illiberal, but in some instances totalitarian.

The conventional wisdom—subscribed to by leftist anti-American ideologues and conservative isolationists alike—is that the recent resurgence of Islamism is due to foreign meddling. When the US and others topple dictators like Muammar Gaddafi or Saddam Hussein, they create a power vacuum that invites political, economic and social chaos, as well as the subsequent rise of radicalised groups. Although there is obviously an historical connection between the collapse of Ba’athist rule in Iraq in 2003 and the rise of IS in 2014, the theory that international interventions are to blame for Islamism’s resurgence masks an uncomfortable truth: Islamism has gone from strength to strength because of its popular appeal.

Hamas is moderate by the standards of IS barbarity, yet the 2006 electoral victory of their Sunni Islamism over Fatah’s relative secularism was a startling demonstration of democracy’s often illiberal consequences. This shock, however, was only the prelude to the deepening ties between democratisation and the erosion of liberal rights and freedoms in various Muslim countries. As the Arab Spring erupted in 2011, predictions abounded of a liberal democratic renaissance in North Africa and the Middle East. Instead, the region’s democratic uprisings precipitated a lurch towards illiberal, and at times outright totalitarian, forms of Islamism.

In Tunisia—birthplace of the Arab Spring—the Islamist Ennahda party stormed to electoral success in late 2011 after decades underground. Democracy then installed the abortive presidency of the Muslim Brotherhood’s Mohamed Morsi in Egypt in 2012, while Gaddafi’s demise has seen Islamist militants expanding their control over Libya’s largest cities. The most striking chapter in this marriage of democratisation and illiberalism is the popular uprising in Syria. This revolutionary war has incubated the violent totalitarian IS on the back of Sunni support.

Illiberal though they may be, there is a great deal of diversity among the Islamists. The relatively moderate Ennahda party has embraced norms of parliamentary democracy, as well as accepting citizenship rather than faith as the basis of individual rights, whilst the genocidal tendencies of IS make it as much a thuggish hate group as an outlet for popular Sunni discontent. Yet from Tunis to Tikrit, democratisation has become the executioner rather than the midwife of liberal rights and freedoms.

Why did political leaders and commentators naively imagine that democratisation would allow liberal rights and freedoms to flourish? This assumption was probably partly the product of a degree of narcissism among the political class in the liberal democratic world. From the vantage point of cosmopolitan global elites who enjoy extensive liberal rights and freedoms, it was easy to blithely believe that peoples around the world would use democratisation to secure similar sets of legal and institutional protections for individual liberty. Whatever its origin, this comforting myth has been shattered in Tunisia, Egypt, Syria and Iraq.

As the international community now recognises, there is an overwhelming moral obligation and a compelling strategic rationale for fighting egregiously illiberal democratic uprisings. Nevertheless, the liberal democratic world must also appreciate the limitations of external efforts to combat violently totalitarian forms of Islamism. Resting as they do on widespread popular support, these messianic movements cannot be turned back simply by degrading their military capabilities and killing their commanders. Rather, holding the line against bloodthirsty jihadists hinges on a battle for hearts and minds that will last years, decades and perhaps even centuries. And unless this generational war against the ideology of Islamism can be won, democracy and liberal rights and freedoms will never comfortably go hand-in-hand.