09/23/2013 03:46 pm ET Updated Nov 23, 2013

Hassan Rouhani's Moment

This week Iran's President Hassan Rouhani will enter the world stage leading his country's delegation at the United Nations General Assembly. It will be the first time that he addresses the world body and unlike his rabble-rousing predecessor he will strike a more moderate and conciliatory tone. He should receive a far different reception then President Ahmadinejad whose speeches became long-winded diatribes that were as memorable for their content as they were for the number of dignitaries who walked out during them. When President Rouhani takes the podium for his speech he could possibly see something that was unthinkable just a few months ago -- senior members of President Obama's foreign policy team listening to him politely.

The recent exchange of letters and outreach to Washington by the new administration in Tehran is not new phenomena. Letters have been exchanged in the past between President Obama and Iran's Supreme Leader Ayatollah Khamenei. There was even great hope for a breakthrough between both countries during the Clinton administration when there was another moderate cleric, Mohammad Khatami leading Iran. Despite great hope of a diplomatic breakthrough nothing came to fruition. President Obama needs to seize what President Rouhani's overtures offer him: a significant foreign policy achievement -- something that has eluded his presidency.

President Rouhani has done much by way of outreach. He has come out domestically and internationally in unequivocal language and has stated Iran does not want nuclear weapons and is against WMD production and use. Iran is looking to come to a deal with the United States on its nuclear program -- one that allays Western fears of weaponization and yet maintains indigenous enrichment at a mutually acceptable level for domestic power generation. In return the Obama administration must not fall victim to domestic constituency such as radical Republicans in Congress or Prime Minister Benjamin Netanyahu of Israel who keep beating the drums of war and want to further isolate Iran with more sanctions. This myopic approach would crater any hope of a deal with Iran because just as the American and Israeli far right shudder at a compromise with Iran so do the hardline elements of President Rouhani's domestic constituency. If they feel that Rouhani's fresh approach and willingness to compromise with the West has fallen on deaf ears then they will demand Iran retrench to its original hostile position.

The most important person in these negotiations won't be in New York this week but he will be watching and listening to every move from afar. Iran's Supreme Leader Ayatollah Khamenei has final say in all mattes with respect to the nuclear program as well as dialogue with the United States. Without his acquiescence President Rouhani would not have been able to move the nuclear portfolio out the Iran's Supreme National Security Council -- and into the hands of the Foreign Ministry under the auspicious of Mohammad Javad Zarif, his new Foreign Minister. Zarif is a veteran diplomat as well as being U.S. educated, he was at one time head of Iran's UN mission. He is known to many inside the State Department and has experience negotiating with American diplomats on issues as sensitive as Iraq and Afghanistan.

In a speech last week Ayatollah Khamenei made to senior commanders of Iran's Revolutionary Guard he called on the need for Iran to show "heroic flexibility" in pursuing its national interest in foreign affairs. This was a signal to the hardline elements of the guard that he favors diplomacy over militarism. More importantly it was a signal that the Iranian leadership, at the highest levels, is preparing their public for a breakthrough with the United States after 34 years of enmity. President Obama should appreciate how far President Rouhani has gone in such a short time -- not only laying the groundwork internationally for rapprochement with the United States but also how he has maneuvered around militant factions in his own country. In the past Iranian presidents, including Ahmadinejad, when looking to negotiate with the United States on various issues such as the nuclear program, were always undercut at home by opposing political factions. This is precisely what happened in 2009 when the P5+1 thought it had a deal with Iran on shipping its stockpile of highly enriched uranium outside the country only to have it undone by politicians inside the country.

President Obama should seize this opportunity. Not only would a photo-op with President Rouhani on the sidelines of the General Assembly be historic, but given the wide range of issues that divide the United States and Iran it would send a powerful message to the rest of the world. Iran has the ability to play a stabilizing role in Syria, Iraq, and Afghanistan if it's incentivized to do so. It has leverage with diverse groups all across the Middle East. President Rouhani will need to come away with more than just President Obama's respect but tangible sanctions relief. Iranian access to the international banking sector through the SWIFT network has been cut off for more than two years now. If Iran were to agree to more intrusive inspections regime under the IAEA and to put limits on its domestic enrichment activities, the Obama administration must reciprocate in kind with significant sanctions relief beyond what has been offered through the P5 +1. Letting Iran back into SWIFT would be a good place to start and send the right message to the Iranian people.

If President Obama fails to embrace this opening and look at President Rouhani as an agent of change then this window will be closed just as quickly as it has been opened. This is the Obama administrations "China moment." Forty years ago President Nixon went against many hawks in his own party to strike a deal Mao Zedong and reconfigure the world order, confounding his critics and America's adversaries. It took tremendous courage and political will to do so. After five years of uneven American leadership in the Middle East, President Rouhani offers President Obama his best chance at lasting foreign policy achievement.