The Taliban (which, in Arabic, means “students”) in Afghanistan and Pakistan are the products of these seminaries, as are militias like Lashkar-e-Taiba and Lashkar-e-Jhangvi, which have mounted attacks on religious sites in India

Turmoil has seized much of the Muslim world. In Syria, a brutal war has already taken 250,000 lives, displaced half of the country’s 21 million people, and sent a million refugees to Europe seeking asylum. In Yemen, the Houthi tribe has risen up against the government, and are now facing Saudi-led airstrikes. Conflicts like these reflect a number of factors, the most prominent of which are the conflicts between Islam’s two sects, Sunni and Shia, and between fundamentalists and reformists.

Syrian President Bashar al-Assad’s Alawite regime enjoys the support of Shia powers, especially Iran, whose regional influence depends on a Shia regime remaining in power. And that is precisely why Sunni powers – most prominently Saudi Arabia – are committed to toppling that regime. Yemen’s government, by contrast, is Sunni-led, and thus has Saudi Arabia’s support, hence the bombings of the Iran-backed Shia Houthis. Unsurprisingly, tensions between Iran and Saudi Arabia have intensified lately, a trend that culminated in the severing of diplomatic relations over Saudi Arabia’s execution of a popular Shia cleric.

The chaos fueled by these conflicts – and by instability in other countries in the region, such as Afghanistan and Iraq –has enabled the rise of some truly contemptible forces, beginning with the Islamic State (ISIS). That group has gained so much influence that US generals have asked President Barack Obama to authorize additional troops to join the fight against it. Moreover, there are reports that the United States may postpone the withdrawal of its troops from Afghanistan, where an increasingly brutal war against the government has enabled the Taliban to gain territory and created an opening for ISIS to become active. ISIS has also penetrated Pakistan.

The religious element of the conflicts raging in the Middle East today is a major reason why they have been so difficult to defuse. The Sunni-Shia schism goes back to the year 632, when the Prophet Muhammad died without indicating how the fast-growing Islamic community should pick his successor. Those who became the Shia believed that the position should remain in the prophet’s immediate family and supported the selection of Ali ibn Abi Talib, the prophet’s cousin and son-in-law. Those who became the Sunni supported the choice of the community’s senior members: Abu Bakr, who had served as a close adviser to Muhammad.

Today, most of the world’s 1.6 billion Muslims are Sunnis. They are widely dispersed, spread over

a vast swath stretching from Morocco to Indonesia. After decades of migration to Europe and North America, there are also strong Sunni communities in several Western countries.

The Shia number 225 million and are geographically much more concentrated. Iran, with 83 million, is the world’s largest Shia-majority country, followed by Pakistan with 30 million and India with 25 million. The “Shia crescent” – including Iran and its immediate neighbors Afghanistan, Azerbaijan, Iraq, Pakistan, and Turkey – accounts for 70% of the sect’s total population.

This geographic distribution is the result of a series of historical accidents, a combination of conquests and (often forced) conversions. Though Islam arrived in Iran by way of conquest in 637-651, the country did not officially adopt Shi’ism for nearly another century, with Shah Ismail I of the Safavid dynasty undertaking in 1501 the forcible conversion of the country’s Sunni population.

Shi’ism spread through South Asia as a result of repeated military incursions by Persia’s rulers into Afghanistan and India. Today, that region’s Shia population is concentrated in urban areas.

Sunni Islam, for its part, was first spread through South Asia by the Sufi saints, most of whom came from Central Asia and preached a more tolerant and inclusive form of Islam than that of the Arabian Peninsula. But the rising influence of Saudi Arabia after the 1970s, when skyrocketing oil prices boosted the country’s wealth considerably, helped to spur the spread of the Kingdom’s dominant and austere Wahhabi sect.

Beyond attracting millions of Muslim workers from South Asia, Saudi Arabia financed the establishment of Wahabbi madrassas along the Afghanistan-Pakistan border. The Taliban (which, in Arabic, means “students”) in both Afghanistan and Pakistan are the products of these seminaries, as are militias like Lashkar-e-Taiba and Lashkar-e-Jhangvi, which have mounted attacks on religious sites in India.

Today’s turmoil reflects a clash of worldviews that is both theological and political. Conservative Sunnis, such as those who adhere to fundamentalist Wahhabism, favor theocratic authoritarian rule, whereas more moderate Sufi Sunnis would prefer liberal and inclusive political systems. The same is true of the Shia. Iran has long stuck to theocratic rule, but now seems to be looking toward reform. Whether the sectarian divide can ever be bridged most likely depends on whether reformists can gain sufficient influence in both camps. If not, the conflict will continue to rage, accelerating the breakdown of regional order we now see.

Burki, former Finance Minister of Pakistan and Vice President of the World Bank, is currently Chairman of the Institute of Public Policy in Lahore

© Project Syndicate, 2016 www.project-syndicate.org