Amid escalating conflict in Yemen and battles in Iraq and Syria, many wonder how the Middle East became seeded with such conflict. One argument frequently made is that of a sectarian division between Sunni and Shiite Muslims, as highlighted by the so-cold cold war between regional powerhouses Iran (Shiite) and Saudi Arabia (Sunni), which most recently have been jockeying for power in Yemen.

Attributing conflict to age-old divides between Sunnis and Shiites is tempting, but although sectarianism helped pave the way for today's ongoing strife, major conflicts in the region have since devolved into seeking revenge for past oppressions or a struggle for geopolitical control. These alternative factors are critical in order to understand conflicts in today’s Middle East.

The Sunni and Shiite sects of Islam date to a disagreement in the seventh century over who should succeed the Prophet Muhammad, founder of Islam. After Muhammad died, his companion Abu Bakr became the new leader, or caliph, of Islam, despite the protests of the supporters of Muhammad’s cousin, Ali.

Ali did eventually become caliph, but not before a serious disagreement had begun over the succession question. Five years later, Ali was assassinated and his followers rejected the leaders of Islam who followed. His descendants became the Shiites, while those who descended from supporters of subsequent caliphs became Sunnis.

Today, the populations of majority-Muslim countries are varying mixes of Sunnis and Shiites: Iraq is a blend of the two, Iran is predominantly Shiite, Saudi Arabia is Sunni, Jordan is Sunni, Syria a blend, and so on.

Iraq And The Birth Of ISIS

In 1991, Shiite Muslims in southern Iraq and Kurds in the country’s north began an uprising against the leader of the country, a Sunni named Saddam Hussein. Fearing that he could be overthrown if Shiites in Iraq joined forces with Shiites in Iran, the dictator launched a brutal crackdown, massacring tens of thousands of Shiites and Kurds and setting the stage for a power struggle rooted in revenge that continues today. After the U.S. invasion of Iraq toppled Saddam in 2003, the U.S. installed a government headed by a Shiite, Nouri al-Maliki, whose sectarian policies alienated and discriminated against Sunnis. By the end of 2012, anti-government protests had begun in some Iraqi cities dominated by Shiites.

Today, Maliki’s policies are part of the reason why the brutally anti-Shiite militants known as the Islamic State group -- also known as ISIS or ISIL -- were able to thrive in the country. Not all Iraqi Sunnis were flocking to join the group and many Sunnis didn’t even necessarily support it. But they did tolerate it or, at the very least, refused to fight it -- whether because doing so might have suggested they supported Maliki, their enemy, or because they sought some form of protection from Maliki’s crackdown on Sunnis.

Proxy War In Yemen

In Yemen’s ongoing conflict, Houthi rebels backed by Iran are facing off against a collapsed government backed by Saudi Arabia, where Yemen President Abed Rabbo Mansour Hadi arrived Thursday after fleeing Yemen’s southern port city of Aden. On Wednesday, Saudi Arabia began airstrikes in Yemen targeting Houthis, who reportedly receive weapons and training from Iran. As Richard Haass, president of the Council on Foreign Relations, described it, “What this means is that Yemen has become the latest locus of Iran-Saudi, Shia-Sunni conflict.”

But a closer look also suggests that among nationals fighting in Yemen is a basic struggle for power between Houthis and tribes that don’t want to give it to them. Iran and Saudi Arabia, competing for regional political influence, have picked their respective sides, in part to prevent the other country from gaining too much sway in Yemen, which is strategically located on a point of access to oil terminals and pipelines.

With Yemen being the home base for al Qaeda in the Arabian Peninsula (AQAP), the country's internal conflict also poses another threat to Saudi Arabia, which had stopped backing Hadi financially after he was deposed. Now, Saudi Arabia is ramping up its support again with airstrikes because it fears that AQAP may grow stronger in the absence of a government that appeared willing to tamp it down. At the same time, Saudis worry that Houthi territorial gains could push members of AQAP over the border and into Saudi Arabia.