NEW DELHI – The United States’ era as a hyperpower has ended, leaving its policymakers to confront difficult questions about their country’s global role.

Should the US continue to act with its traditional sense of embodying an exceptional destiny in and for the world, or should it retreat into isolationism?Of course, every US president must pay lip service to the country’s "exceptionalism.” President Barack Obama did so most recently in September, when he declared that "what makes us exceptional” is that we act "with humility, but with resolve.” Despite his desire to end US entanglements in the wars in the greater Middle East, he appears determined to give life to the claims of American exceptionalism.Evidence of this was seen recently when Obama and Iranian President Hassan Rouhani became the first leaders of their respective countries to have a conversation in more than three decades. Rouhani – a reputed moderate, whose week-long visit to New York for the United Nations General Assembly included a series of unprecedented diplomatic encounters – offered truly conciliatory rhetoric to his US counterpart. Despite catcalls from conservative US politicians and media, Obama’s reaction to Rouhani was statesmanlike.Just as Rouhani’s trip was coming to an end, Obama initiated a phone call with him. While the conversation was brief, a senior Obama administration official reported that the two leaders had a "shared sense of urgency” over the upcoming nuclear talks, and that an agreement there "could open the door to a deeper relationship.”Renewing the long-fractured bilateral relationship would require both parties to overcome strong domestic opposition. When Rouhani returned to Iran, conservative protesters hurled eggs and shoes at him. And in the US, instead of giving Obama time to negotiate a nuclear deal with Iran in a less charged atmosphere, hardline conservatives like Florida Senator Marco Rubio have called for the imposition of a new round of economic sanctions.America’s experienced diplomats seem to be more supportive of the move to strengthen the bilateral relationship. Suzanne Maloney, a former State Department official, expressed cautious optimism, stating that "it is early days and it will require a lot of testing, but Mr. Rouhani has been more ambitious than I would ever have hoped.”The journalist Steve Clemons went further, stating that "rapprochement with Iran would be the biggest positive shift in global affairs since the end of the Cold War and the normalization of relations with China.” America’s failure to take advantage of this opportunity, Clemons continued, would be its "biggest strategic error since the Iraq invasion.”The question is how Obama, with limited room for maneuver domestically, can explore this potentially game-changing development. Given Iran’s continued progress with its nuclear program, heeding conservative demands for a return to hostility and antagonism would be a mistake. Indeed, in this case, not talking amounts to having no strategy at all – a seriously risky proposition. Even if the relationship does remain icy, lines of communication that have now been opened must remain so.To be sure, nobody believes that many decades’ worth of mistrust and resentment can be overcome in an instant. Iranians cannot forget the US-led coup that overthrew the nationalist Mohammad Mossadegh six decades ago, and Americans remain bitter about the invasion of the US embassy in Tehran in 1979, which resulted in more than 50 American diplomats and staff being held hostage for 444 days.But, while statesmen cannot rewrite the past, they can shape a better future. And the historic issue today is Iran’s nuclear program. As a signatory to the Nuclear Non-Proliferation Treaty, Iran has the right to develop its nuclear capacity, but only for peaceful purposes. Within this framework, there is space for the US and Iran to find common ground, if both sides adopt a realistic approach.Obama’s other option – to launch a military attack on Iran’s nuclear facilities – is a non-starter. Such an attack has scant chance of success, particularly after America’s costly and self-defeating misadventures in Afghanistan, Iraq, and Libya.Fortunately, although both sides have drawn "red lines,” recent events have created powerful momentum for progress. Though Iran has declared that removal of its stockpile of 20% enriched uranium from the country is its red line, Foreign Minister Mohammad Javad Zarif has expressed a desire to agree on a "road map” for resolution. Zarif also says that the nuclear crisis could be resolved within a year, with a deadline for the talks ensuring that neither "side would think the other is killing time to pursue some other goals.”These circumstances call for the best of American exceptionalism. Iran, home to one of the world’s oldest continuous civilizations, may be willing to end decades of hostility – an outcome that would have a profound influence on the wider Middle East. The US must not allow its isolationist impulses – or its conservative hardliners – to prevent it from seizing this diplomatic opening.Jaswant Singh served as India’s finance minister (1996, 2002-2004)Copyright: project-syndicate.org