In Syria, Go Big or Stay Home

FROM liberal internationalists to hawkish conservatives, a chorus of influential voices in Washington is suggesting that American intervention in Syria would also do serious damage to Bashar al-Assad’s close ally, Iran.

Military action in Syria would demonstrate, so the argument goes, that America is serious about enforcing its red lines. Impressed and crestfallen, Iran’s recalcitrant mullahs would scale back their nuclear zeal and conform to international nonproliferation agreements.

However, given the fact that any intervention by the Obama administration is likely to be tentative and halting, rather than an overwhelming show of military force, it is not likely to end Syria’s civil war or intimidate Iran’s rulers.

The sort of intervention needed to bring about a decisive rebel victory would require more than no-fly zones and arms. It would mean disabling Mr. Assad’s air power and putting boots on the ground. America would have to take the lead in organizing a regional military force blessed by the Arab League and supported by its own intelligence assets and Special Forces. After that would come the task of reconstituting Syria and mediating its sectarian conflicts. As the war in Iraq painfully demonstrated, refashioning national institutions from the debris of a civil war can be more taxing than the original military intervention.

Because it would take all of this to oust Mr. Assad and end the violence, America must accept the need for a robust intervention. There is no easy solution or middle ground. Moreover, rather than intimidating Iran, a less-than-decisive American intervention in Syria would do the opposite. It would convince Iran’s leaders that America doesn’t have an appetite for fighting a major war in the region.  

There is something curious about the debate gripping Washington. Although the Assad regime has massacred more than 70,000 of its citizens and appears to have violated all norms of warfare by using chemical weapons against civilians, calls for robust intervention are muted.

The legacy of Iraq looms large. A war-weary nation that has sacrificed so much on the battlefields of the Middle East is reluctant to embark on new campaigns. Neither the Obama administration nor its Congressional critics seem to have an appetite for nation-building. And there is a reluctance to admit that half measures like arming the rebels or establishing a no-fly zone are unlikely to end the suffering of the Syrian people in the face of a determined Alawite minority, led by a vicious Mr. Assad, who has no qualms about carrying out ethnic cleansing in a struggle to the death.

A prolonged war in Syria would offer Iran the same advantages that America’s invasion of Iraq did. Once the United States settled into the task of reconstituting Iraq, generals, politicians and pundits insisted that a second front couldn’t be opened in the Middle East. As Washington tried to sort out Iraq’s troubles, it ignored Iran’s mischief and subversion.

While Iran enjoyed immunity from American military force as a result of Washington’s preoccupation with Iraq’s civil war, Iranian proxies in Iraq systematically assaulted American troops with I.E.D.’s and helped derail their mission. In the meantime, Iran’s mothballed nuclear infrastructure was taken out of storage and refurbished.

If a very reluctant Obama administration does becomes entangled in Syria, it is likely to treat Iran with the same degree of caution as the more hawkish Bush administration did — avoiding any direct confrontation with Iran and refraining from issuing ultimatums about Iran’s nuclear program. The result would be an emboldened Iran willing to cross the nuclear threshold and assert its dominance throughout the region.

To be clear, there is no doubt that a decisive rebel victory in Syria and the fall of the Assad dynasty would constitute a major setback for Iran, given that Syria has always been Iran’s most reliable pathway to its proxy Hezbollah. But a rebel rout is highly unlikely without full-scale, decisive American intervention.

Facing public pressure to stop the violence, Washington may soon embark on an incremental intervention that would gradually deepen American involvement without producing a decisive outcome. But such half measures won’t impress Iran’s hardened rulers, who are engaged in a fundamental struggle for the future of the Middle East.

Pleased with Mr. Obama’s much vaunted pivot to Asia, the mullahs in Tehran are already convinced that America seeks deliverance from its Arab inheritance. A major American intervention would give them pause; a reluctant intercession in Syria by a hesitant America would only enhance their resolve.

Paradoxically, an intervention intended to persuade Iran’s leaders of the viability of American red lines could instead convince them that their nuclear program is safe from American retaliation.