Mr Obama and his administration have persisted in seeking this goal in the teeth of the severest possible opposition. The United States’ regional allies – Israel and Saudi Arabia in particular – mince no words in declaring their opposition to Iran, and to any relaxation of the US stance on Iran. Israel’s mercurial prime minister, Binyamin Netanyahu, has denounced the deal as a “historic mistake” with all the resources at his command, and has promised to lobby the US Congress to stall or scuttle it - a not inconsiderable threat, given Israel’s clout on Capitol Hill. In any case, Congressional Republicans – and some Democrats – are willing to vote against the deal, and Mr Obama will have to lobby hard. However, it is clear that he has shown the appetite to wipe out existing lines in the sand, and to persist with diplomatic methods. He has reversed two of the longest antagonisms in US history — against Cuba and against Iran. He has been wary of intervention in Syria. It remains to be seen if he can add to this list, in his time remaining in office, with a correction of one or two other major US policy missteps — such as its continuing enabling of Pakistan’s militarist establishment.
For India, of course, such a reversal would be considered overdue. It is often lame-duck presidents who can be prevailed upon to invest political capital in such forward-looking policies. As for India’s position on the Iran deal itself, it will no doubt welcome the stability that the mainstreaming of Iran will provide to West and Central Asia. Yet it will not all be good. India has not taken advantage of Iran’s period of exile sufficiently — it should have used its privileged position to embed itself in Iran’s security, commercial and diplomatic establishment. As Iran opens up, India will struggle to maintain the special relationship, economic and diplomatic, that has aspired to creating and maintaining with Iran.