Iran has long sought to spread its Islamic revolution into neighboring Iraq. With late Iraqi leader Saddam Hussein and the US out and Shiites in control, Iraq’s leaders are now intent on rebuilding their country as a regional Shiite power. But first, they must pacify radical Sunni elements and unite the divided Shiite sects. The divisions have opened the door for Iran’s long-sought ascendancy in Iraq. Iranian revolutionary Shiite Islam - arguably more than anything else - has become the Islamic Republic’s foremost strategy of attaining influence in Iraq.The writer is an Intelligence Analyst with Max-Security Solutions, a geopolitical risk consulting firm based in Israel.As is the case with most religious groups, Shiites are not monolithic and there are notable ideological and political differences among them. For centuries, Iraq has historically been the premier source for Shiite ideology, much of it stemming from the southern city of Najaf. However, Saddam’s secular dictatorship systematically targeted leading Shiite clergymen, thereby forcing many into exile in neighboring Iran.That said, the return of thousands of Iraqi Shiites and clergymen - many now learned in Iranian dogma - has become a major catalyst for spreading Tehran’s religious message throughout Iraq. With their return, Iran has sought to supplant or push aside the traditional Shiite leaders from the "quietist" religious school in Najaf with revolutionary Islamic teachers who have trained and studied revolutionary Islam in Qom, Iran.Unlike in previous times, Iran is taking a careful and calculated approach to increasing its influence in Iraq. Iran learned early on that spreading the Islamic Revolution by sheer force would not work. This failed when Iran attempted to impose its version of Islam upon Iraq when the Ayatollah pushed the fighting into Iraq during their bloody eight-year war in the 1980s. Today, on the other hand, Iran is careful not to antagonize or write-off prominent Shiite parties. It certainly favors certain parties over others, most notably those which are deemed most receptive to Iranian ideology. However, in doing so, it is diligent not to overstep its hand and avoid bellicose rhetoric towards Iraq. The Western mind might question how much influence religious doctrines can bring. But in a conservative Muslim state, molding Iraqi Shiite ideology around the Iranian model provides an unprecedented scale of leverage for the Islamic Republic in Iraq. For those seeking to contain Iran’s ascendancy, the decline of Najaf and the rise of Qom’s clout in Iraq is surely a troubling sign. As stated previously, the predominant bodies within the Shiite camp, the Islamic Dawa Party, ISCI, and the notorious Sadrist Movement, all share a certain level of beneficial contact with Iran.To that point, much of the internal Shiite debate centers on several issues: which type of Shiite ideology is best suited for Iraq, the country's relations with the senior Shiite power, Iran, and the very nature of the country's political platform – i.e. national unity or federalism. Each party has their own vision for the country, whether based on religious nationalism, such as the Islamic Dawa Party (to which Prime Minister Nouri al-Maliki belongs) or the more federalist approach of the powerful Islamic Supreme Council of Iraq. The latter envisions a possible autonomous Shiite entity in the south, with Basra as its power center.On the other hand, the hard-line Sadrists maintain a predominantly religious nationalist approach and remain crucial to preserving a level of Shiite unity and controlling Baghdad. Unlike the religious nationalists that control Iraq, Iran would most likely prefer parties with some federalist tendencies to rule the country. The motivation for such a stance is simple to understand: Iran can assert more influence through federalism than a powerful central government.But more than political influence, the religious factor is foremost to Iran’s ambitions in Iraq. Recent reports indicate that Shiite cleric Grand Ayatollah Mahmoud Hashemi Shahroudi is being promoted as a possible successor to the aging spiritual leader for Iraqi Shiites, Ayatollah Sistani. Posters of Sharoudi are popping up in Sadr City, and his presence is growing in the holy city of Najaf.If Shahroudi indeed takes over for Sistani, it would mark a major step in Iranian influence over Iraq. Sistani hails from the “quietest” school of Shiite Islam, while Shahroudi was trained in Qom, is Iranian, and is closely linked with Iran’s religious elites. In addition, Shahroudi is seen as in touch with the newly encouraged and energized Shiite generation that currently rules Iraq. Although admired by many, other Iraqis associate Sistani with generations of subjugation under Hussein. Shahroudi’s rise is indicative of both Iran’s ambitions to push its version of Islam within Iraq and is of one example of their strategy to do so.In the end, their strategy will take time and require careful maneuvering, with much of this activity occurring under the radar and out of the headlines. But there is no doubt Iran is committed to ascending in Iraq and furthering its hegemonic ambitions in the region. To do so, the mullahs have decided that spreading revolutionary Islam, above all else, offers them the best chance of increasing their hold over Iraq and so far, they are right.