By Barbara Slavin

The last few days have witnessed major milestones between the United States and Iran, including implementation of a landmark nuclear deal, a prisoner exchange and resolution of a financial dispute that goes back to the severing of diplomatic relations between the two countries 36 years ago.

It’s all been rather breathtaking given the dismal record of the past, when dialogue between the two governments was intermittent at best and cooperation rare. But questions remain about whether this paradigm shift will survive the Barack Obama administration.

In public and private remarks, American and Iranian senior officials hailed diplomacy for delivering important victories to both sides.

Obama, addressing the nation from the White House on Sunday, reminded the public, “For decades, our differences with Iran meant that our governments almost never spoke to each other. Ultimately, that did not advance America’s interests.”

President Barack Obama delivers a statement on Iran and the release of five Americans from Iranian detention at the White House on Jan. 17, 2016. (Reuters)

Less than two hours earlier, Iranian President Hassan Rouhani said, “Our country has a big power called the power of diplomacy. There were many who did not believe in this power but it has turned out that the win-win policy was the accurate one.”

Along with satisfaction, there was immediate skepticism in some quarters about the negotiations, and whether or not diplomacy can produce more breakthroughs. Republican presidential candidates predictably criticized the prisoner exchange as lopsided, if not foolhardy, suggesting it would only encourage Iran to take more “hostages” in the future.

Critics warned that provisions in the nuclear agreement that unfroze billions of dollars in Iranian oil revenues and allowed Iran to return to world markets – in return for major curbs on Iran’s nuclear activities — would only embolden Iranian intervention in the Arab world and opposition to Israel.

GOP frontrunner Donald Trump complained on Twitter that Iran was getting seven prisoners while the US got only five – among them Washington Post reporter Jason Rezaian, former Marine Amir Hekmati and Christian pastor Saeed Abedini, who flew out of Iran on Sunday.

After attacking the Obama administration, Trump then took credit for the release of the Americans, asserting that it was his tough rhetoric against Iran and reputation as a dealmaker that convinced the Islamic Republic to let the Americans go before he assumes the presidency.

In Iran, there were complaints that Obama slapped new sanctions on Iran as soon as the plane carrying the American detainees departed Tehran. U.S. officials conceded that the sanctions – over Iran’s testing last fall of ballistic missiles in violation of UN resolutions – had been delayed so as not to jeopardize freedom for the Americans, or Iran’s implementation of key steps of the nuclear deal.

There were also questions about whether the raft of deals concluded last week – including paying Iran $1.7 billion for US weapons ordered by the Shah but not delivered after the revolution – was all that the two sides could achieve before Obama leaves office. (Rouhani can run for another four-year term in 2017.) 

In their remarks on Sunday, both Obama and Rouhani suggested there was more that they could do.

“We have a rare chance to pursue a new path – a different, better future that delivers progress for both our peoples and the wider world,” Obama said. “We need to take advantage of that.”

Iran’s President Hassan Rouhani gestures at the conclusion of his press conference in Tehran on Jan. 17, 2016. (AP)

Rouhani, in response to a question at a press conference about whether Iran could resolve its deep divisions with the Saudis to bring peace to Syria and Yemen, said that the nuclear deal – reached after two years of talks between Iran, the five permanent members of the UN Security Council and Germany – “can serve as a model for settlement of regional disputes.”

Most Arab countries, however, especially Saudi Arabia, fear that a richer Iran is a more dangerous Iran that will increase support to its partners and proxies throughout the Middle East. An Arab artist captured the mood with a cartoon that showed the West and Iran shaking hands, fists clenched together over a prostrate Arab.

For ordinary Iranians, a major question is just how much economic benefit they will receive from resources their government is getting under the nuclear deal.

A man looks at exchange rates seen through the window of a currency exchange shop in Tehran’s business district on Jan. 17, 2016. (Reuters)

Rouhani, at his press conference, tried to dampen expectations by comparing sanctions removal to reclaiming a garden that had been occupied by others. “You need to work on the land and soil and plant the trees,” he said. Fruits won’t “happen overnight.”

Iraninan diplomats worked hard to get sanctions lifted before Feb. 26 parliamentary elections in hopes that pragmatic candidates would get a boost. But reports that the Guardian Council – a powerful body largely appointed by Supreme leader Ayatollah Ali Khamenei — had disqualified large numbers of reformers in an initial vetting process put a damper on political change.

Still, the fractious Iranian system showed remarkable unity in supporting the nuclear negotiations, the release of 10 American sailors who blundered into Iranian waters last week and the exchange of US prisoners for Iranians jailed in the United States.

Indeed, a novel feature of the secret negotiations that led to that exchange was American contact with Iranian intelligence officials who usually do not interact with Westerners.

In a background briefing with reporters on Sunday, a senior U.S. official said American diplomat Brett McGurk met with an Iranian intelligence official and other non-diplomatic Iranian representatives in private meetings hosted by the Swiss government over the past 14 months.

“What happened today in getting American citizens home, for being able to do this, [involved talking] with elements of the Iranian system we don’t normally engage with,” the official said. For multilateral negotiations over Syria to succeed, these same security officials will likely also have to be engaged.

In his remarks, Obama again referred to Iran as the Islamic Republic of Iran – something his predecessors have been loath to do – and said he wanted to speak “directly to the Iranian people.”

“Yours is a great civilization, with a vibrant culture that has so much to contribute to the world  in – commerce, and in science and the arts,” Obama said. “Following the nuclear deal, you – especially young Iranians –  have the opportunity to begin building new ties with the world.”

Barbara Slavin is Acting Director of the Future of Iran Initiative at the Atlantic Council in Washington.