I still remember when, seemingly overnight, a flurry of posters went up across my university campus in west London, proclaiming the coming of the “khilafah,” or caliphate—an Islamic state encompassing all Muslims and ruled by a successor to the prophet Mohammed. That was two decades ago.

Hizb ut-Tahrir, the radical group behind the posters, copied and distributed them across dozens of British universities, building up such popularity that they attracted as many as 10,000 Muslims to their conferences at one time. These students were relentless, constantly visiting other Muslims on campus and imploring them to get involved in fundamentalist campaigns, usually through a mix of guilt-tripping, cajoling, and good, old-fashioned peer pressure.

They were unflinchingly confident that a caliphate would soon arise. But hardly anyone thought that, two decades later, not only would one come to the Middle East, but its legitimacy would be questioned so vociferously by Muslims themselves.

In under a year, the Islamic State in Iraq and the Levant (ISIL) has sparked a huge theological debate about whether its actions are intrinsically Islamic—one that is unprecedented in recent times. In one sense, this debate is irrelevant: both sides have declared the other to be apostates and the result has been ideological stalemate. In another sense, however, it matters deeply to Muslims tempted by the idea of living under a caliphate. Is ISIL indeed the successor to the prophet Mohammed’s legacy? And if so, is there a religious obligation to pledge support?

But debating whether ISIL is Islamic or not misses the big picture, largely because it treats the group in isolation. The key to understanding ISIL is not in theology, but in the historical and political context laid decades before Abu Bakr al-Baghdadi declared his territory to be the Islamic State in June of 2014, anointing himself the caliph for all Muslims.

Hizb ut-Tahrir (HuT) is a particularly significant prelude to this story. Founded in 1953 in Jerusalem by a scholar named Taqiuddin al-Nabhani, it has one aim: to unify all Muslim countries under a caliphate ruled by Sharia law. It believes this caliphate is central to Islam, and that Muslims, by definition, cannot reject its call.

HuT grew rapidly in the 1980s and ’90s, especially in the UK, as a second generation of British-born Muslims came of age. It attracted supporters by running campaigns (usually against Islamophobia), and provoking clashes between Muslims and non-Muslims. One of its former adherents, Maajid Nawaz, later wrote: “We were encouraged by Omar Bakri [HuT’s then-leader] to operate like street gangs, and we did, prowling London, fighting Indian Sikhs in the west and African Christians in the east. We intimidated Muslim women until they wore the hijab and we thought we were invincible.”

HuT wanted to show Muslims that the West couldn’t accommodate them. Most notoriously, in 2005, they were accused of pushing 16 year-old Shabina Begum to sue her school for not letting her wear an all-covering jilbab. She lost. HuT was eventually banned from most university campuses due to its virulent anti-Semitism and inflammatory stunts.

It may now be a shadow of its former self, but Hizb ut-Tahrir created a powerful legacy. Its charismatic leader, Omar Bakri, went on to form al-Muhajiroun, which further perfected the art of media-grabbing stunts designed to pit Muslims against others. Bakri’s infamous protégé, Anjem Choudary, now leads the outfit (which constantly changes its name), and some of his adherents have gone on to commit highly publicized acts of terrorism, or join up with ISIL. More pertinently, it created a desire among many western Muslims for a caliphate.

But the acceptable means of achieving that end have shifted from raising awareness to extreme violence. That has happened partly because of events elsewhere.

ISIL’s penchant for violence against so-called apostates isn’t a new development. It beheads prisoners just like neighboring Saudi Arabia has over decades, for trivial offences. Its brutality is partly derived from the Taliban, which perpetrated extreme violence against minorities and women in Afghanistan and Pakistan for years before 9/11, hidden from the gaze of CNN and the BBC. ISIL’s callous disregard for history, destroying artifacts at the Mosul Museum last week, for example, mirrors what the Taliban did to the Buddhas of Bamiyan in central Afghanistan.

In other words, ISIL is a culmination of Islamist politics and thinking that has percolated over the last 30 years or more. Its adherents are strongly attracted by the idea of belonging to a caliphate supposedly created by mandate of their prophet. “Everyone can contribute something to the Islamic State, as it is obligatory on us,” said Canadian ISIL-supporter Andre Poulin, also known as Abu Muslim, in a video last year. “If you have knowledge on how to build roads and houses, you can be of use here.” It was a pitch expertly crafted for ex-HuT members.

When Muslims say ISIL’s actions are outside the Islamic mainstream, they want to deny it any legitimacy in the eyes of other Muslims—and non-believers who may hold the moderate majority responsible for the violence of fractional zealots. Many say it is perverting and distorting Islam, and its actions are thus wholly un-Islamic. Calling the insurrection an “Islamic State” just plays into this delusion, they say. Even President Obama has been hesitant to lend ISIL an explicitly “Islamic” label.

In reply, others say it is difficult, if not impossible, to separate ISIL from Islam, given that its ideology, actions, and communiqués repeatedly cite the Quran or hadiths (specific teachings of Mohammed). It is a religious group with carefully considered beliefs, Graeme Wood argued in a recent cover story for The Atlantic. And, as such, we cannot discount ISIL’s Muslim identity. In an essay for The Daily Beast, Asra Nomani, co-director of the Pearl Project, and Hala Arafa, an Egyptian journalist, write that ISIL’s language and explanations are dripping with traditional, orthodox Muslim rhetoric. How can one logically pretend ISIL is not “Islamic” when almost everything they do is coated in Quranic doctrine? It is a reversal of delusion.

But the complexities grow. Shadi Hamid of the Brookings Institution says ISIL ignores two fundamental aspects of Quranic interpretation from the earliest days of Islam: “asbab al-nuzool”—context and intent. Though Murtaza Hussain, writing for The Intercept, rightly points out that even though ISIL exudes Islamic orthodoxy, most mainstream Muslim scholars reject their interpretations of the religion—though they are rarely asked, in the Western press, about this.

The widely signed “Open Letter to Baghdadi” made a similar point, that ISIL’s view of the world is, in fact, a relatively recent and fringe perspective among Muslims. Just because its fighters wrap themselves in a thick blanket of conservative Islamic theology doesn’t mean they have a more profound understanding of the faith, its history, and its tenets.

This isn’t an unusual claim. Extremist groups of Christian, Jewish, Buddhist, and Hindu backgrounds are also frequently accused of taking cultural history or scriptures out of context to justify violence. One of India’s most famous prisoners is a radical Hindu swami who quotes Vedic scripture to justify the terrorist activity he is accused of. Groups in India accused of nationalistic extremism, such as the Shiv Sena and Bajrang Dal, also envelop themselves in Hindu imagery and history.

But while the theological arguments that result from these events are important, they are ultimately circular. Extremists always have a goal: exploit legitimate grievances and warp the scripture to advance their position. Like HuT, ISIL feeds on ideas and grievances that many Muslims can identify with.

ISIL supporters on social media casually dismiss criticism from respected imams and scholars in the Middle East as puppets of hated Western governments, for example. Clearly, academic and theological criticisms won’t be enough to lessen their grip in the short or long term—because the problems that inspire ISIL-style extremism are not, at their core, academic or theological. So, whether ISIL’s actions are fundamentally “Islamic” is a moot point.

It’s more important to ask whether Muslims should desire a caliphate under Sharia law, more than relatively open democracies where all religions are treated equally. A Sharia state, by definition, is an unequal state. It affords Muslims a higher status than dhimmis, non-Muslims, who are obligated to pay jizya, a special tax. A Sharia state would also, by definition, have blasphemy laws that would inevitably be used to oppress minority groups, as they already do in Pakistan and Bangladesh, and most Middle Eastern countries.

Attempts to engineer theocracies are not exclusive to Muslims, of course. Right-wing nationalist parties in India seek to transform the country into a Hindu state. The Khalistan movement seeks to create a state governed by Sikh principles. Some Jewish settlers in the West Bank wish to drive out local Palestinians, for certain, but not to unite with Israel—rather, to form “Judea,” a state governed by Halakha, which in many respects parallels Sharia. All of these theocratic fantasies are problematic for similar reasons. But extremists of other faiths aren’t particularly close to realizing the goal.

What differentiates ISIL is that it made it happen, and this perhaps explains its relative popularity. ISIL offers something concrete for some Muslims, wavering on the edge of fundamentalism, to grab hold of. Thus, debating whether they are un-Islamic shirks away from the more important task of questioning the fundamental premise on which ISIL and other Islamists have flourished—the perceived communitarian need for a caliphate.

ISIL’s political ideology hasn’t sprung up in a vacuum over the last year, or even in the time since 9/11. It evolved over decades, even centuries, incubated in groups that included HuT and Wahhabi preachers from Saudi Arabia. For this reason, the key to undermining ISIL isn’t to declare them apostates—since the impact of that is clearly negligible—but to challenge the khilafah ideal of most Islamist movements. That ideal has been the rallying cry and driving force behind ISIL and the movements that led to it, and only when it’s successfully challenged will such groups be relegated as truly marginal.