Reuel Marc Gerecht of the American Enterprise Institute gives readers an excellent insight into the dynamics of the Iraqi/Iranian relationship:
Clerical Iran's primary objective is to ensure that Iraq remains destabilized, incapable of coalescing around a democratically elected government. Such a government supported by Iraq's Shiite establishment is a dagger aimed at Tehran's clerical dictatorship. Intra-Shiite squabbles do matter, and this one between Iraqi clerics who believe in one man, one vote and those who believe in theocracy is an enormous difference of opinion. We should not be fooled by the publicly cordial relations that usually exist between clerics of Najaf and Tehran. Najaf's position on democracy is an explicit negation of Ayatollah Ali Khamenei's and his associates' right to rule Iran.
The clerical regime is currently handcuffed to Iraq's democratic process and timetable. All of the principal groups through which Iran hopes to exercise influence in Iraq--the Iranian-created Supreme Council for the Islamic Revolution in Iraq (SCIRI), the Dawa (or "Islamic Call") party, and the Sadriyyin, followers of Muqtada al Sadr, the young clerical firebrand who has been engaged in a spiritual tug-of-war with the country's traditional clergy--are committed now to the election process.
Iran has probably been pouring money into Iraq, to all three of these Shiite groups, which don't share much affection for each other, and in the case of the Dawa and the Sadriyyin, have had distinctly mixed, often hostile, emotions about things Iranian. Both the Dawa and the Sadriyyin have regularly belittled Grand Ayatollah Sistani for his "Persianness" and snarled at clerical Iran's habit of talking down to the Iraqi Shia.
Tehran is trying to align itself with a variety of often contradictory parties because it cannot overtly oppose the democratic process in Iraq, in which an increasing number of Iraqi Shiites are passionately invested. Like Washington, Tehran really doesn't know what is going to happen on Jan. 30 and after, though it no doubt hopes that Sunni Arabs abstain from voting en masse, thereby supercharging sectarianism. If a civil war could be provoked, Iraq's democratic experiment and moderate Shiite religious establishment would probably both collapse.
If the neighboring one-man, one-vote clerics can be downed and America can be physically and spiritually drained in Iraq, then the two most feared, disruptive forces in Iranian politics--Western-oriented Iranian youth and pro-democracy dissident clerics--can be further weakened. The more the Americans bleed next door, and the clerical regime definitely believes America is on the run in Iraq, the less likely they'll have the will to take out Iran's nuclear program.
In Iraq, the U.S. ought to have two obvious goals. To crush the Sunni insurgency before it can provoke the birth of an exclusive, angry Shiite political identity willing to do to the Arab Sunnis what the Baath once did to the Shia. If such an identity is born, it is most unlikely democracy can prevail. Washington must thus ensure that the democratic process in Iraq, regardless of the violence, keeps on rolling. As long as it does, clerical Iran will not be able to gain much traction inside the country. SCIRI, the Dawa and the Sadriyyin are not puppets controlled by Tehran; the rising power of southern Iraq's Shiite tribes, which historically have looked askance at clerical direction from any quarter, will further frustrate Iranian influence.
It is hard to overestimate the importance for the world of American success in Iraq. Failure is unthinkable, which makes those on the left in both Europe and at home who lead the cheers for our enemies in Iraq all the more despicable.