In 1979, the Iranian Revolution officially created a Shiite republic. Iran is now the largest and most militarily powerful Shiite country, and its power has enabled Tehran's clerics to support Shiite communities and thus enhance its influence in the Arab world. But expanding its influence was not always easy. Iran tried to leverage its own ethnic Azeris to use the Shiite majority in Azerbaijan to its advantage. However, until 1991, Azerbaijan was part of the Soviet Union and, as such, a secular nation. Its secularism, in turn, made it resilient to Shiite overtures.
Despite the vicious fighting that occurred during the Iran-Iraq War in the early 1980s, Tehran was able to establish a foothold in Iraq, made possible by the animosity between the regimes in Baghdad and Damascus. Indeed, Syria became an early Iranian ally, thanks in part to the fact that it had an Alawite regime ruling over a majority Sunni population. Syria's rulers also helped Iran develop Hezbollah into a major political and military force.
Two other events were instrumental to the expansion of Iran's regional clout: In 1989, the Iran-Iraq War ended, and, somewhat coincidentally, the Lebanese civil war was resolved. This left Hezbollah, Iran's proxy group, as Lebanon's single largest political entity. A few years later, Iraq invaded Kuwait, bringing forth the first Gulf War. For Iran, the war was incredibly beneficial because it weakened the government in Baghdad, which previously had protected the Gulf Cooperation Council from Iranian encroachment.
Subsequently, Iraq's minority Kurds and Shiites, whom Tehran had supported for years, began to exploit the growing weakness of the Iraq regime. By the time the United States defeated Saddam Hussein in 2003, Iraq was ripe to fall under Iranian control. And fall it did, giving Iran an arc of influence from Tehran to the Mediterranean Sea.
