Aki Peritz insists that Iran is biting off more than it can chew in Iraq:
Iran can only go so far to pacify Iraq with its own forces. The IRGC and its Shia proxies are reviled in Sunni-majority areas, and an effort to hold territory by these groups would eventually cause a major backlash among the population. So Iran would have to eventually withdraw, leaving a power vacuum, again, in those areas.
More broadly, many of the socio-economic and sectarian drivers that brought Iraq to this horrific juncture would remain in place after the shooting stopped. A semi-failed state containing thousands of virulently anti-Shia veteran fighters on its western border will remain a long-term national-security nightmare for Tehran.
The economic impact of a war-torn Iraq must also be considered, as Iran sends some $5 billion in non-oil exports to their neighbor every year. But, as for the rest of the region, Bruce Riedel believes it will be Iran’s enemies who suffer if the intervention is successful:
Saudi Arabia long ago lost the battle for influence in Iraq, but it will see its role further diminished with both a hostile ISIS and a hostile Iran splitting the pie on its northern border. If Iran emerges as the savior of Iraqi Shiites, the Shiites of Bahrain, Kuwait and the kingdom’s eastern province will be further inclined to see Iran as their savior, too.
Since Israel defines Iran as its greatest regional rival, it is also a loser. Certainly, moderates in the Arab world will be increasingly squeezed between extreme Sunni groups and Shiite Iran. They will be less inclined to take conciliatory steps toward Israel that will be unpopular and dangerous. Jordan is the most vulnerable moderate state.
If Iran helps stop ISIS outside Baghdad, the impact will be felt in Syria. The Iranians and their Hezbollah allies will gain further credibility as the only force that is actually on the ground resisting al-Qaedaism. Tehran will have emerged as the leader of a block of Shiite-dominated states, each looking to Iran for critical security support.
(Photo: Iranian President Hassan Rouhani speaks during a press conference in the capital Tehran on June 14, 2014. Iran may consider cooperating with the United States in fighting Sunni extremist fighters in Iraq if Washington acts against them, Rouhani told journalists. By Atta Kenare/AFP/Getty Images.)