Only six months ago, a deal on Iran's nuclear program appeared impossible. But after the Iranian people elected the pragmatic Hassan Rouhani as president, a 17-minute phone conversation between him and President Barack Obama, and several weeks of secret talks, the deal is now a reality.
How did this stunning change of events come about? In my book A Single Roll of the Dice - Obama's Diplomacy with Iran, I point out that both sides have lacked the political will to break the institutionalized enmity between them. I listed three factors on the US side that, alone or in combination with each other, needed to change before a full-scale investment in diplomacy could be made.
First, there had to be a significant geopolitical shift in the region that simply rendered the continuation of the US-Iran enmity too costly. Second, the domestic political landscape in Washington had to change so that the key vested interests opposing a US-Iran deal would no longer be decisive. Or third, the president had to muster enough political strength and will to decide to do the right thing for the US national interest, regardless of the domestic political price that would be inflicted on him.
To varying degrees, all three factors have changed in the past six months.
Regionally, the strategic interest of the US and two of its key allies in the region - Israel and Saudi Arabia - have been diverging on several important fronts: on Iran, on the Israeli-Palestinian conflict, and on the Arab uprisings. Washington seeks a nuclear accord with Tehran to avoid both a nuclear Iran and war with Iran. The Saudis and Israelis, on the other hand, fear that any improvement of relations between Tehran and Washington will legitimize Iran's role in the region and increase its influence at their expense.
[I]t is difficult to imagine that the American public would be so ferociously opposed to a relatively minor military engagement in Syria but favour a potentially unending war and invasion of Iran.
On the regional balance of power, Martin Kramer, a fellow at the conservative Israeli Shalem Center points out the main issue of contention: The American belief that the regional status quo is unsustainable - the Arab populations are rising and America's Middle East strategy has to adjust to this reality instead of continuing to back pliant Arab dictators. Kramer disagreed: "In Israel, we are for the status quo. Not only do we believe the status quo is sustainable, we think it's the job of the US to sustain it." On this issue, the Saudis and Israelis tend to agree. An Arab official who was briefed on talks between President Obama and King Abdullah bin Abdulaziz Al-Saud told the New York Times the Saudi monarch was unwavering in his opposition to the largely Shia pro-democracy protests in Bahrain. "King Abdullah has been clear that Saudi Arabia will never allow Shia rule in Bahrain - never."
Secondly, the debacle over Syria made it clear that the domestic political landscape in the US has changed dramatically. As Obama sought support from Congress for an attack on Syria, the US population ferociously resisted, flooding Congress with phone calls. The most credible threat that was issued throughout this episode was not Obama's threat to bomb Syria, but the American people's threat to unelect members of Congress if they supported the war. In spite of support for the war from the American Israel Public Affairs Committee (AIPAC), a lobby often viewed as invincible, which is also in favour of confrontation with Syria's ally Iran, the American people prevailed. Obama could not get support from Congress. AIPAC was defeated.
This dramatically changed the landscape because it showed that the politically safe position was not to be hawkish and pro-war, but to be sceptical of military action and favourable towards diplomacy. While this has not fully spilled over into the Iran debate, it is difficult to imagine that the American public would be so ferociously opposed to a relatively minor military engagement in Syria but favour a potentially unending war and invasion of Iran.
Thirdly, the commitment of the President to diplomacy - in spite of its potential political fallout - could not be any stronger right now. "Tough talk and bluster may be the easy thing to do politically, but it's not the right thing for our security," he said a day after the deal had been struck. Once Rouhani was elected and the White House concluded that he was serious and committed to diplomacy, the US president mustered the same dedication, regardless of the domestic political price. He did so partly because it was the right thing to do for US national security, but also because Iran is now - paradoxically - the lowest hanging fruit in the Middle East. There is no other issue in the Middle East that has as high of a likelihood of being solved. Here, unlike Syria, Egypt and elsewhere in the region, the US president had a good chance of making a difference.
If the parties reach a final, comprehensive deal, this will undoubtedly be a game-changer in the region. But it will also come about to some extent because both the region and the political dynamics in Washington have already changed.
Trita Parsi is President of the National Iranian American Council and author of A Single Roll of the Dice - Obama's Diplomacy with Iran.
The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.