Will Syria deal spur US-Iran diplomacy?

The diplomatic compromise that has, for now, averted U.S. air strikes on Syria could portend a breakthrough in the stalled negotiations over Iran's nuclear program. That's according to President Barack Obama, who linked the two issues in an interview on Sunday and revealed an exchange of letters with Iran's President Hassan Rouhani that prompted some to speculate over a possible meeting between the two when both address the U.N. General Assembly in New York next week.

In an interview on ABC's "This Week with George Stephanopoulos," Obama did not reveal details of the letter exchange, but he made clear that U.S. concerns about Iran's nuclear ambitions are a "far larger issue for us" than Syria's chemical weapons incident. And he argued that diplomacy backed up by a credible military threat had prompted Syria to comply with international demands on its chemical weapons program and could have a similar impact on Tehran's nuclear calculations.

"My view is that if you have both a credible threat of force, combined with a rigorous diplomatic effort, that, in fact you can strike a deal," Obama said. Regarded as a relative moderate, Rouhani has also made conciliatory statements toward Washington since coming to office last month.

Both leaders have reason to seek progress towards resolving the stalemate: The Syria debacle has left Obama's foreign policy approval ratings at an all-time low, while Iran's support for the Assad regime has hurt its regional reputation.

"Iranians have taken a hit and Americans have taken a hit, (which) has sharpened the interests of both sides," said Reza Marashi, research director at the National Iranian American Council and a former official at the U.S. State Department's Office of Iranian Affairs.

Trita Parsi, president of the council, told Al Jazeera that U.S. failure to engage with Iran earlier in Syria's civil war had been a mistake that jeopardized prospects for a diplomatic solution.

"With Iran one of the fighting parties on the ground, you need to involve them," he said.

Obama and Rouhani are both due to address the General Assembly on Tuesday next week. But despite media speculation, a White House spokeswoman said there are currently no plans for the presidents to meet on the sidelines of the event, a statement confirmed by Rouhani in a tweet on his recently opened Twitter account – another sign of Iran's enhanced willingness to take diplomacy into a new direction.

The political risks for both presidents to engage in what would be the first meeting between an Iranian and American leader since 1977 -- when Jimmy Carter met the then-shah of Iran, Mohammad Reza Pahlavi -- are obvious. Both Rouhani and Obama are likely to be criticized by hardliners for engaging in diplomatic talks with the enemy.

"The biggest risk is that you are attacked and beat up by extremists in your own political system at home," Maharashi said. "Obama and Rouhani have a finite amount of political space," he said, in what foreign diplomats call a "window of opportunity" to improve their political relationship.

In the short or medium term, "a political process is only sustainable if you can show results," he said.

Parsi said the stakes are high when dealing with negotiations at the top diplomatic level.

"When the negotiations are only taking place at the technical level … the cost of failure is not high enough. When you have foreign ministers involved or (players) at the presidential level, the cost of failure increases exponentially," he said.

In an effort to reassure more hawkish allies and elements in Washington, Obama warned Iran to avoid the mistake of believing that since the U.S. has taken no military action against Syria, it would not move against Tehran's nuclear program.

"They shouldn't draw a lesson that we haven't struck, to think we won't strike Iran," Obama said. "On the other hand, what they should draw from this lesson is that there is the potential of resolving these issues diplomatically." 

Tehran denies seeking nuclear weapons, and the U.S. intelligence assessment holds that Iran's leaders have not decided to build such weapons. But they are steadily acquiring the capability to build nuclear weapons should they decide to do so.  

Israeli Prime Minister Benjamin Netanyahu, who takes a more hawkish view of Tehran's intentions, has hinted at possible Israeli military strikes on Iran should he deem diplomacy a dead end. 

"In any case, Israel must be poised and ready to defend itself, by itself, against any threat – and this capability and readiness are more important now than ever," he said. 

Netanyahu has called on Tehran to hand over all its uranium enriched above 3.5 percent and to stop any further purification. Israel is widely assumed to have the Middle East's only nuclear arsenal -- a point repeatedly made by Iranian officials, who have refused to compromise on what they say is Iran's right to enrich uranium for peaceful purposes.  

Lisa De Bode contributed to this report. With wire services.