WASHINGTON — As Secretary of State John Kerry flies back from Saudi Arabia to New York for his second meeting this week with Iranian Foreign Minister Mohammad Javad Zarif on April 22, some US officials and outside experts are thinking about how the functional diplomatic channels that have been established with Iran over the past few years between the Obama and Rouhani governments might be maintained in the next US presidential administration.

The channels established between the United States and Iran during the last three years of intense Iran nuclear deal negotiations that culminated in implementation of the landmark deal, the Joint Comprehensive Plan of Action (JCPOA), in January, have included unprecedented one-on-one contacts most frequently between Kerry and Zarif and their top deputies, but also between other Cabinet chiefs — US Energy Secretary Ernest Moniz and Iranian Atomic Energy chief Ali Akbar Salehi, and last week, for the first time, between US Treasury Secretary Jack Lew and Iranian Central Bank governor Valiollah Seif, as well as consultations between dozens of midlevel diplomats and experts. Indeed, as Kerry meets Zarif in New York on the sidelines of the signing of the UN Paris climate agreement, new US Undersecretary of State Tom Shannon and Stephen Mull, the State Department’s JCPOA implementation czar, will be meeting in Vienna with Iranian Deputy Foreign Minister Abbas Araghchi and others on the eight-member Joint Commission established to oversee implementation of the Iran nuclear deal.

But for all the frequency and growing to almost normalcy of US-Iranian official contacts in recent years, after decades in which that was taboo, they have yet to be institutionalized by formal US-Iran diplomatic relations, which were broken off after the 1979 Islamic Revolution and subsequent hostage crisis. What’s more, US-Iran normalization is not a realistic near-term prospect, Obama has said, even as he has ushered in historic shifts with Myanmar and Cuba. The prospect of rapprochement is even more fiercely rejected by Iranian Supreme Leader Ayatollah Ali Khamenei, who casts it as a fundamental threat to the nature of his regime.

Obama is willing to engage with the Iranians when useful, and has shown he is willing to break old taboos when he traveled to Cuba in March, the White House’s Ben Rhodes said April 21. But from the White House’s perspective, it is Iran putting the brakes on deeper engagement with the United States, Rhodes said.