Bassam al Zarka, a sophisticated and highly intelligent Salafist leader in Egypt, eloquently explains the answer to the question Muslims around the world have been asking since 9/11: Whose Islam is it? The faith of Salafists like himself? The religion practiced among more secularist Muslims? The religion interpreted among state-sanctioned scholars, such as those at Al-Azhar university?

His first response, when I met him in December in his well-appointed home in Alexandria, was to dismiss secularism. “Trying to plant the seed of secularism in Muslim societies is like trying to plant a tree near the equator,” he told me. Zarka holds firm to the belief that various interpretations of Islam should be accepted, and that includes the way Islam is practiced among Shia Muslims, who some Sunni Salafists believe are kufar, or unbelievers.

“Are the Shia real Muslims?” I asked him.

“Whoever doubts God is kufar. But I disagree with those Salafists who say the majority of Shia are kufar. My reason is that they are ignorant and lack knowledge. They are dhalal, which means ignorance and deviating from righteousness. Not everyone received knowledge.”

Zarka’s perspective is not necessarily shared by some Sunni Muslims, and these include believers who are not in extremist groups, such as ISIS. The question of who is a believer and which interpretations of Islam are truly part of the faith is a central question that Muslims are struggling to answer, particularly since the Arab uprisings began in 2011. Although this is an arguable and controversial assertion, the Arab uprisings and the collapse of the nation state — to some degree artificially created by colonist powers — placed more of an emphasis on religious, rather than nationalist identities.

Religion and how it is interpreted is playing an increasingly significant role in the conflicts across the Middle East. This is what is new about my book, The New Sectarianism: The Arab uprisings and the Rebirth of the Shi’a-Sunni Divide. Many scholars and analysts who are writing on this subject believe the wars are motivated primarily by power plays, regional politics and control over territory. However, if you read the hostile and aggressive Twitter feeds in Arabic and the Arabic media, it is obvious that religion has something to do with it. Both Shia and Sunnis believe the other is trying to extinguish their sect — and this is one of the many reasons the violence has increased.

Governments in the region — particularly Shia Iran, and Sunni Saudi Arabia, Turkey, Bahrain and the United Arab Emirates — fuel this perception because it serves their geopolitical interests. All these governments want the sect they lead to have more power in the Middle East. In some cases, government propaganda campaigns were very effective in driving a wedge between Shia and Sunnis in their countries. The uprising in Bahrain, which is often overshadowed due to the scale of violence in Syria and Iraq, is a perfect example of how an uprising that began with a collective goal to create a more pluralistic form of governance evolved into a deep-seeded sectarian conflict.

What was clear then and is abundantly clearer now is this: Religion is being democratized among Sunni Muslims. There is no one religious authority or religious leader who can declare which interpretation of Islam should be supreme. Everyone has a say. Although this has been happening since Islamic political movements gained traction in Arab societies, beginning in the 1970s and gaining significant momentum in the 1990s, the Arab uprisings have further diluted any centralized authority on religious interpretation.

I traveled to Egypt in December to interview Salafists and scholars from Al-Azhar to demonstrate the magnitude and expansion of the concern over the religious difference between the Shia and Sunni. Egypt is a country with less than 1% of Shia, according to U.S. State department statistics. Yet, many Egyptians believe there is a “Shia threat.” Therefore, even in an outlier state with no history of sectarianism, the regional conflict, which began in Iraq and later Syria, is taking its toll.

So what are the theological differences that cause the Sunnis to believe the Shia are either deviators or unbelievers? First and most importantly, some Shia have stated in the past that the companions of the Prophet during his lifetime became apostates after his death. The Sunnis hold the companions of the Prophet in high esteem and even chose one, Abu Bakr, to be his successor. Abu Bakr became the first Caliph after Mohammad’s death; his daughter, Aisha, was one of the Prophet’s wives. This led to the eventual split in Islam: The Shia believed the Prophet’s rightful successor should have been from his bloodline.

The second reason the Sunnis view the Shia with suspicion concerns the figure of Aisha herself. Some Shia believe she committed adultery while married to the Prophet. The Quran states she did not have extra-martial affairs. Thus, the Sunnis believe that anyone who doubts the Quran, on this as on any other point, is an apostate.

Third, the Shia and Sunni differ over supreme religious authority. The Shia developed a complex and ambivalent view of relations between religion and the state. By contrast, among the Sunnis, support for the ruler, even if he is corrupt or unjust, represents a religious obligation grounded in the Quranic injunction to obey “those who have been given authority among you.” But the Shia believe in the doctrine of the Imamate — the recognized authority over all aspects of Shia community life by the direct heirs to the Prophet Mohammad, beginning with his son-in-law, Ali ibn Abi Talib, known among them as the First Imam. According to the Shia texts, Ali and his 10 successors were killed by agents of the rival Sunni Caliphs.

To avoid such a fate and preserve the viability of the community of believers, the Twelfth Imam, Mohammad al-Mahdi, went into hiding. He announced in 941AD that he was severing his last earthly ties and would return only at the end of time to usher in a reign of perfect peace and justice. The Shia believe he hid himself in a cave below a mosque in Samarra, in modern-day Iraq. This cave is blocked by a gate the Shia call Bab-al-Ghayba, or The Gate of Occultation.

This is one of the most sacred sites in Shia Islam, and the faithful gather there to pray for the return of the Twelfth Imam. The doctrine of Occultation is simply the belief that God hid Mohammad al-Mahdi away from the eyes of men to preserve his life. The Shia believe that eventually God will reveal al-Mahdi to the world and he will then create peace on earth.

As al Zarka, who was instrumental in revising the Egyptian constitution when President Mohamed Morsi was in power, explained that waiting for the Hidden Imam is considered an affront to the essence of the Sunni tradition. “This is the utmost (evidence) of being lost,” he said. “After Mohammad died on earth, no one else is authorized to speak for God. But the Shia believe the Supreme Leader of Iran has divine powers and they believe that, if the Hidden Imam appeared, he would speak for God.”

Some Sunni Salafists with 12 million to 14 million Twitter followers tweet against the Shia day and night. And they use major battles in the wars in Syria and Iraq to justify whatever religious claim they are making on Twitter that day. Those who say religious justification is reductionist and the conflicts are driven primarily by politics overlook centuries of Islamic history. Particularly for the Shia, the battle of Karbala has remained at the center of their narrative of Islamic history. During my years living in Iran from 1998-2001, this was abundantly clear and is even more true today.

The Arab uprisings began with a seemingly secular cry, “The people want to overthrow the system.” In most countries, religious motivations were, at first, conspicuously absent; but, 5 years on, the initial unity has eroded into societal conflict in some countries and all-out war in others. Instead of agreed-on goals of social justice and a different form of governance, religious differences and how Muslims define themselves have emerged as newly salient characteristics throughout Arab society.

Throughout history, competing groups, sects, and schools of Islamic law all struggled to define the faith for a diverse and often-contentious community of believers, but the Arab uprisings brought identity and religion once again to the fore. A core issue in the post-Arab uprising era is the question: Who is a true believer and who is a nonbeliever? This exclusionist mind-set is most evident in the sectarian conflict between Shi’a and Sunni Muslims, which poses a serious threat to the stability of regional states and to stakeholders in the wider world, including the United States and its allies.

One of the many reasons sectarianism is so intractable and will, unfortunately, plague the Middle East for years to come, is that all players in the violent conflict claim to have a monopoly on religious truth. Whose Islam is it? Is it that of the Salafist, who wants to return to how he says Islam was practiced during the time of the Prophet Mohammad 1,400 years ago? Or that of the banned Muslim Brotherhood leader in Egypt? Or the leader of a Shi’a militia in Iraq? Or the Islamic State of Iraq and Syria (ISIS), the Islamic State? Each party believes its religious knowledge is sacred and true.

From its beginnings in the 1970s until today, a key to the power and appeal of modern Islamism—encompassing an array of groups from the nonviolent Muslim Brotherhood of Egypt to the violent al Qaeda and ISIS—has been the process of defining “the Other.” Members of traditional religious institutions have been left behind in what has become an interpretive free-for-all.

This exclusionist claim to religious truth is not new, nor is it exceptional to Islam. This historical phenomenon shares some characteristics with other revealed faiths. As sociologists of world religions have long noted, the death of a charismatic leader, prophet, or seer deprives the nascent community of access to revelation and sets the stage for the rise of a caste of priests, lawyers, and bureaucrats who claim the authority to interpret the holy teachings. The sacred texts remain unchanged, whereas how they are interpreted—and by whom—become questions of utmost importance.

These same circumstances also introduce the very real likelihood of dissent, fragmentation of the community, and the emergence of distinct sects or groupings, each asserting a monopoly on religious truth. In the world of Islam, this problem has proved particularly acute. With the arguable exception of the earliest days of Islam, there has never been anything resembling a consensus figure or institution of religious authority among the Muslims. As a result, Muslims worldwide have been left vulnerable to a succession of claimants, many backed by the use of force, in what have proved ultimately to be doomed efforts to secure such a mandate.

Much of the social and political unrest that characterizes Islamic history, from the murders of its earliest leaders, to medieval rebellions, to the rise of Osama bin Laden and the birth of the self-proclaimed Islamic State in our own century, reflects this same internal logic.

In other words, the longing for Muslim religious identity reflects an internal debate that has been, quite literally, centuries in the making. Since the death of the Prophet Mohammad in 632 CE, the question of legitimate religious authority has plagued the worldwide community of believers. Who, then, is a good Muslim? And who gets to decide? These questions are no less relevant today than they were in the seventh century, and differing responses during the intervening centuries have brought forth aspiring prophets, visionaries, and revolutionaries demanding the right to dictate the proper contours of the faith to their fellow Muslims, often with the threat of death or damnation.

During the postcolonial period, a new generation of essentially secular leaders—such as Egypt’s Gamal Abdel Nasser and Libya’s Muammar Gaddafi—backed their nationalist policies with claims of religious sanction and used local religious institutions to solidify their hold on power. It is no accident that Egypt and Libya later emerged among the most prominent battlegrounds between dictatorial state power and popular demands for self-determination.

Today’s charismatic religious ideologues first began to make their presence felt during the 1970s, laying the foundation among Arab societies for a religious revival that continues to the present. Shi’a and Sunni communities—the former in reaction to the Iranian Revolution in 1979 and the latter in response to the developing power of the Muslim Brotherhood in Egypt—began to associate their long-established religious beliefs and practices with personal identity, supplanting a largely manufactured and fragile loyalty to the relatively new phenomenon of the nation state.

As these religious revivals gathered momentum, the efforts by states to invent traditions to secure the idea of nationhood began to collide with a growing Islamism. Over time, this battle steadily eroded the power of many of the region’s rulers, but also challenged established religious institutions, which were widely, and correctly, seen as having placed the interests of the state over those of the ummah, the larger community of Muslim believers.

By the time the Arab uprisings erupted into their full fury in early 2011, there was already fertile ground for instability, insecurity, and violence. Although it is imprecise to say the Arab uprisings alone produced violence in the name of religion, it should be understood that the overarching ideologies of Islamism and nationalism, which had been developing for decades, locked horns. In addition to this state-societal competition, a struggle has developed within Islam, primarily between Shi’a and Sunni Muslims, but also within each of these communities, penetrating many aspects of Arab society. In each Arab country, this competition has a different history and is now being played out in different ways. There is no consistent frame and thus the Shi’a-Sunni conflict must be analyzed separately in each country.

So, is the Shi’a-Sunni conflict fundamental? Can the gulf be bridged? These questions divide experts in the East and West. The fundamental question is whether religious identity now trumps other identities, including ethnicity, tribe, and national affiliation. If so, because the religious difference is, by its nature, unresolvable, this would mean the violence now sweeping the Middle East is intractable. If, however, other struggles over other identities are just as important to stability, then there is hope the conflict will subside or be subsumed into other less combustible and more manageable arenas.

The argument I put forth, through narratives, rhetorical analyses of non-state actors, and interviews with a variety of religious figures, is that even if there ever should be agreement over what constitutes being an Iraqi, a Syrian, an Egyptian, a Bahraini, or a Lebanese, the recent uprisings have brought religious identity to a place of new importance in Arab societies—a development with at least 30 years of history behind it.

Those who argue that religious difference is not the fundamental cause for violence posit another theory: it is the geopolitical rivalry between Shi’a Iran and Sunni Saudi Arabia, and their proxies and clients doing their bidding on the ground, that are shaping and directing the conflict. Although this is certainly a significant driver of the conflict, the violence would not be as profound if religion were not also being contested. Essentially, longstanding notions of religious identity and sectarian affiliation have supplanted the postcolonial project of Arab nationalism, thereby creating the opportunity for violent extremist groups, such as ISIS and al Qaeda, to fill the resulting vacuum.

Contrary to conventional wisdom, extremist groups such as the Islamic State did not appear out of nowhere. Rather, these extremists are benefiting from all the conditions described earlier. They have also found support from those who have been marginalized economically and politically—not necessarily from the Arab uprisings alone, but from everything that helped spark the revolts in the first place.

This significant development took Western governments by surprise. It was not until the civil and sectarian wars in Iraq and Syria became so bloody that Western scholars and governments acknowledged the Sunni-Shi’a conflict was real and that it probably had something to do with religion. What is most alarming is that Western thought, having experienced 30 years of modern Islamism, did not understand that religion and ideology were destined to become the main currencies among societies in the Arab world.

As the Arab uprisings toppled dictators, Western media outlets, political leaders, and others viewed the turmoil as being led exclusively by secular actors and groups engaged in civil disobedience in the name of Western-style democratic reform. Herein lies the origin of the seductive but highly misleading notion of an “Arab Spring,” a dangerous misnomer that has led many a politician and commentator astray. Now, it is clear that those who led the revolutions in some countries will not finish them.

Many analysts, government experts, political leaders, and academics refuse to see extremist religious sentiment and practices as anything but an epiphenomenon of more familiar and more comfortable factors, such as institutional failings, economic backwardness, traditional geopolitics, ethnic difference, entrenched antimodern attitudes, and so on. Although these conditions certainly are playing a role in some Arab states, without religious identification the conflicts would not have flared to the degree they have done today.

At the same time, it is vital that scholars, analysts, and others in the field not shy away from acknowledging the role that some prominent contemporary readings of Islam have in the propagation of violence and extremism. It must be possible to distinguish between the faith as a whole—that is, the faith as Scriptural command—and its various and conflicting interpretations throughout the many centuries following the Revelation.

Traditionally, sectarianism can be understood as a set of institutional arrangements determining loyalty and affiliation. Today, however, the increase in sectarian conflict is primarily the result of the collapse of authoritarian rule and a struggle for political and economic power, and over which interpretation of Islam will influence societies and new leaderships.

In states such as Bahrain and Lebanon, where the Shi’a make up approximately 70% and 40% of the population, respectively, the prospects of democratic governance alarm the Sunni. As a result, democracy is viewed largely as part of a subversive Shi’a agenda. Although the underlying goal of the Arab uprisings was to move toward a more just style of governance, the Shi’a “threat” may provide those Sunni-dominated governments still standing with powerful justification to retain authoritarian rule.

During the past three decades, as Sunni Islamist movements gained widespread popular support, the Shi’a also began to mobilize, despite restraints imposed by their governments. Broadly speaking, the Shi’a, once a seemingly weak and alienated community within Arab Islam, are now demanding their rights and reaching for greater political influence—from Saudi Arabia to Bahrain and Kuwait.

Just how profound are the challenges still facing the Shi’a was documented recently in an opinion survey conducted by the Pew Forum on Religion and Public Life, a Washington, DC–based research institute. The study showed a widespread belief in most Arab countries that Shi’a are not real Muslims.

A central challenge to the stability of the Arab world lies with the tension between Islam’s complete integration of the religious and political realms and the European state apparatus imposed by colonial power during the 19th century, without regard for Muslims’ beliefs, practices, or modes of communal governance throughout the preceding 1,100 years. Thus, the modern state failed to take root.

Instead, postcolonial rulers floundered to cobble together systems that mimic elements of the modern sovereign state, grounded in nationalist and pan-Arab claims of legitimacy. The relative ease with which the recent Arab rebellions toppled many of these regimes and badly shook others merely underscores their fragility, instability, and illegitimacy.

Yet, the nation state remains the preferred frame through which the outside world views the conflicts raging across the Arab Middle East. This book challenges this predominant discourse. The increasing power of nonstate actors—who are even more influential after the Arab uprisings—makes any notion of the nation state essentially irrelevant.

The outside observer must also resist the impulse to parse the many expressions of Sunni-Shi’a contestation—whether political, social, or economic—into discrete, independent units in such a way as to ignore or downplay the dispute’s fundamentally religious nature. In other words, this sectarian conflict may be, and often is, expressed in forms that appear recognizable to the outsider as simple rivalry between communities over, say, land use, water rights, political power, economic opportunity, or access to education. However, its very persistence and seeming intractability must be understood as flowing directly from religious differences and their associated religious identities that this difference has conferred on both Shi’a and Sunni.

This same fundamental tension infuses meaning, form, and purpose into all natures of disputes. Thus, the Iran-Iraq War of the 1980s and today’s geopolitical struggle between Iran and Saudi Arabia are both cast by all parties as recapitulations of the Shi’a-Sunni rivalry, the origins of which lie in idealized notions of the seventh century.

State rivalry feeds societal sectarian sentiment and vice versa. This combustible top-down and bottom-up bigotry along sectarian fault lines will, ultimately, alter the map of the Middle East from what it has been since the fall of the Ottoman Empire. This is the reason to draw world attention to the sectarian conflict.

Lastly, on a personal and intellectual level, I must note that I wrote this book as further evidence that religion in Arab society matters—not only in how it is exploited and instrumentalized by extremists, moderate Islamists, and dictators alike for political purposes—but also how it evolves perpetually and is perceived and practiced among the vast majority of Muslims. Arab women do not wear headscarves because of pressure from their husbands or because they cannot afford to buy shampoo, as one prominent Egyptian leader tried to convince me during the 1990s. Similarly, Shi’a and Sunni today are not battling it out over territory alone; they are fighting for history and memory.