Nation & World

As anti-government forces in Syria's violent uprising have increased the pressure on President Bashar Assad to step down, Iran, his main Middle East supporter, also finds itself under siege, undermining a once-powerful partnership and longtime foe of the United States, which has been imposing stiff economic sanctions on both countries.

Some U.S. officials and political analysts see the possible downfall of Assad as an event that could further undermine Iran as its economy reels under the sanctions imposed to get Tehran to suspend its nuclear program.

The departure of Assad, the thinking goes, not only would threaten to sever Syria from Iran, which has long been a goal of the United States and its Arab allies, but also could deprive Iran of its main means of projecting power in the Middle East. If Assad were to fall, Iran would lose its conduit for providing military, financial and logistical support to Hezbollah in Lebanon and Hamas in Gaza. Both groups, which oppose Israel and are considered terrorist organizations by the United States, have vast arsenals of rockets and other weapons.

Moreover, the sanctions on Iran have severely impeded its ability to provide financial aid to Assad (let alone Hamas and Hezbollah), whose treasury has been depleted by the uprising and sanctions on Syria. Another senior administration official said Iran had nevertheless tried its best to prop up Assad, adding that "you would see Assad fall faster if they weren't there."

Syria is likewise important to Iran's efforts to assert its influence over the region, particularly because it borders Lebanon, which provides access to Hezbollah, and Israel, which Iran has declared its enemy.

Ali Banuazizi, a political-science professor at Boston College and a co-director of its Middle Eastern and Islamic Studies Program, said, "To put it bluntly, if Iran is a threat, then one way to weaken that threat would be to weaken Syria and to help the anti-Assad movement in Syria."

The weakness of the Syria-Iran axis represents a stark turnaround from a year ago, when Assad's grip on power seemed assured and Iran was describing itself as the inspiration for other Arab Spring uprisings and Islamist awakening that would subvert America and its allies. Iran even sent two naval vessels through the Suez Canal to Syria last February — for the first time in more than 30 years — in what the Iranians called a message of peace and friendship.

The uprising in Syria, now in its 11th month, has caused extreme discomfort to Hamas, the Palestinian Islamist organization that has been based in Damascus, Syria, for years. Friday, Khaled Meshal, Hamas' leader, left Damascus with no plans to return. Earlier in January, Ismail Haniya, Hamas' prime minister in Gaza, visited Turkey, a former Assad ally that is now perhaps his most powerful regional critic.

It is by no means a certainty that Assad, who has repeatedly rejected calls for his resignation, will depart soon, despite the increased pressure on him on the streets of Syria and at the U.N. Security Council, where an effort by Western powers and the Arab League is under way to force him aside.

Iran has been one of the few conspicuous allies of Assad that has not abandoned him. Except for Assad's minority Alawite sect, other components of Syria's fractured sectarian mosaic have no affinity for Iran. Many Syrians now view Iran as siding with their oppressor. There have been at least three instances in recent weeks of abductions of Iranians in Syria by anti-Assad forces.

The most notable was the seizure last month of five Iranians, whom Iran's state-run media called engineers but anti-Assad groups said were military advisers. In a video posted online by a unit of the insurgent Free Syrian Army, which claimed to hold the Iranians, one of the men identified as a hostage said the five had been "involved in suppressing and shooting ordinary Syrians," and urged Ayatollah Ali Khamenei, Iran's supreme leader, "to order the Iranian military personnel who suppress the Syrians to be repatriated from Syria, so we can also return home."

Iran has continued to publicly recite Assad's version of the uprising — that it is terrorism financed by foreign powers hostile to Syria. Khamenei added his voice Tuesday, denouncing what he called "the interference of America and its allies in Syrian domestic issues."

At the same time, U.S. officials said there was growing evidence that Iran was helping train and equip Syrian security forces.

In early January, the commander of Iran's Quds Force, Qassim Suleimani, visited Damascus, raising suspicions that Iran was advising Assad on how to quash the uprising. The Quds Force, part of the Islamic Revolutionary Guard Corps, conducts operations outside Iran.