Building on the interim deal announced over the weekend is now a question of political will, conviction and mutual trust. In an era where it is often said that the idea of the "conviction politician" is dead, this is an historic opportunity to revive this attitude for as the sociologist Max Weber reminds us, "the ethic of conviction and the ethic of responsibility are not opposites. They are complementary to one another."
On all sides, there is strong doubt, criticism and pressure which attempted to derail the process over the past few months and will act as brakes to the reality of a longer-term deal. These must be resisted wherever possible as history teaches us that major geopolitical moments which have the potential to change the world require our leaders to hold firm in the face of pressure and to display political courage.
History teaches us that political deals require strong convictions and a leap of faith from all sides. On the 50th anniversary of the assassination of President Kennedy it is timely to remember the courage and patience he showed in the face of belligerent advisers during the Cuban Missile Crisis. His resolution meant the world ultimately avoided global nuclear war. Twenty years later, President Nixon's visit to China was an enormous political break with the past given 25 years of no diplomatic contact and took a huge amount of political skill from him and his adviser, Henry Kissinger, to open up secret and trusted lines of communication as prerequisites for the visit, especially as Nixon had been elected on an anti-Communist ticket.
Indeed, the role of secret negotiations is often a necessary element of this courage. They have again been front and centre in the brokering of this interim deal with the Sultan of Oman, Qaboos-bin-Said, trusted and respected on all sides, and with a strong legitimacy across the whole region and not just the major players, providing the diplomatic cover, venue and influence for the preliminary talks.
The Northern Ireland conflict seemed one of the most intractable of our times but it was through consistent, long-term, and often secretive engagement in the 1990s from firstly John Major's Government and then through Tony Blair, with the on-going support of Bill Clinton, in the face of huge general public opposition and scepticism, that allowed the hitherto vacuum of trust to be built into the basis of common ground.
Such political courage hasn't always come from outdated notions of the "west" though. Gandhi's personal perseverance on Indian freedom and unswerving commitment not just to the end, but to the means, of passive resistance was the core driver of Indian independence. In the face of countless arrests, prison sentences and a decades long campaign to undermine him from all quarters makes this all the more remarkable. It also proves that political courage and will takes different forms according to the context in which they operate and the political actors involved.
Such political conviction, flexible where necessary, will allow all sides, and particularly Iran, which is a proud nation, to save face and become the positive force for good in the region and beyond we know it can be. It will though demand unprecedented levels of courage from our 21st century political leaders.