The nuclear deal signed between Iran and the P5+1 nations is a watershed event in international politics and will have a lasting impact on the future of west and south Asia. This may sound implausible since the deal, on the face of it, appears to have done nothing besides putting a cap on the "breakout" time for Iran, and that too a debatable one. Iran has been able to preserve its nuclear rights while getting most of the international sanctions against it lifted. It has acquiesced to international surveillance, but only with its assent. And yet, it has left open a window by agreeing to the reimposition of sanctions if it fails to curb its nuclear programme to acceptable limits and the gradual withdrawal of the arms embargo and missile sanctions. There is no doubt that world powers have walked an extra mile to meet Iran, but Iran has also walked a distance to join hands with them. It is this displacement that holds out the promise for the future because it proves that shibboleths can be discarded if diplomacy is persuasive enough. Both the representatives of Iran and the United States of America have walked the fine line in this game of persuasion. The animosity between these two nations has complicated politics in west Asia for years. The US's efforts at isolating Iran, which it saw as a prime member of the "axis of evil", ended up fuelling Iran's nuclear ambitions while consolidating autocratic regimes in the region. The rapprochement between the two thus shifts the paradigm according to which west Asian politics has been structured so long. As a new ally of the US, Iran emerges as a counterweight to both Israel and Saudi Arabia, a factor that has been drawing these long-time US allies and Iran-baiters together. That could mean more antagonism, but if the US plays it right, it could get a never-before-imagined coalition against the Islamic State of Iraq and al-Sham that is destabilizing west Asia.

The US's refashioned ties with Iran also frees India from several constraints on its relations with Iran. India can go back to refurbishing its ties with its second-most important oil supplier, long-time trading partner and most crucial link to central Asia. More important, Iran's friendship is India's only hope if it has to retain its relevance in the emerging power structure in south Asia once the Americans leave Afghanistan.