The American Prisoners Just Left Iran. But Kerry Almost Got Them Out Months Ago.

ANDREWS AIR FORCE BASE, Maryland -- A Swiss plane carrying American citizens, including a Washington Post reporter, who were released from Iranian prison on Saturday departed Tehran early Sunday morning. The Americans were freed as part of a prisoner release deal -- the result of 14 months of high-stakes secret negotiations between the U.S. and Iran.

John Kerry is relieved that Jason Rezaian, Amir Hekmati, Saeed Abedini and Nosratollah Khosrawi-Roodsari are finally free. But the secretary of state thought he had secured their release months ago.

Last July, just before the U.S., Iran and five world powers announced they had reached an agreement on Iran's nuclear program, Kerry had a conversation about the prisoners with Iranian Foreign Minister Mohammad Javad Zarif, and President Hassan Rouhani's brother, Hossein Fereydoun, in Vienna. “They nodded their heads, and we thought, ‘We’re gonna get it done,’” Kerry told reporters aboard a red-eye flight from Vienna to Andrews Air Force Base early Sunday morning.

In November, Kerry and Zarif met again in Vienna, where they were attending Syrian peace talks. Afterward, they went to Zarif's hotel room and spoke again about the prisoners. “We actually shook hands, thinking we had an agreement,” Kerry said. “I thought it was done.”

Kerry was deliberately vague about what happened next, but when Zarif took the proposed agreement back to Tehran, at least one Iranian government agency objected. “So we went back to work,” Kerry said.

“Javad and I had agreed,” he continued, referring to Zarif. “We knew this was going to happen. We had to work out the modalities of it happening.”

Zarif and Kerry continued to meet, while Brett McGurk, head of the State Department's counter-Islamic State coalition, ran a separate diplomatic track with different Iranian officials as part of the effort to keep the prisoner negotiations separate from the then-ongoing nuclear talks.

The biggest obstacle was whittling down the Iranians' list of requests to something that was within “our principles and our standards,” Kerry said. “Iran asked for a lot of people."

"They fought very hard -- for a long period of time this didn’t move because of the people they were asking for,” he continued, suggesting the Iranians' original list of people they wanted the U.S. to release included people accused of murder and drug-related offenses. 

“Believe me, it’s hard,” Kerry said. “When somebody says to you, ‘Hey, you give us this guy, we’ll let them all out.’ And you have to say no. And you know you’re keeping people in a not very nice place for the next whatever number of months.” 

Ultimately, the two countries agreed on seven Iranians: three who were serving prison time and four who were awaiting trial. All seven were facing charges related to violations of nuclear sanctions -- which were lifted on Saturday. “So there was a symmetry here,” Kerry said.

All seven of the Iranians released are legally allowed to stay in the U.S., and some have indicated that they do not want to return to Iran.

Critics of the prisoner agreement, namely Republican lawmakers and presidential candidates, argue that any type of swap or exchange is unjust. Their logic is that Iranians in the U.S. were facing publicly announced charges and had access to an open trial, whereas the Americans held in Iran were charged, convicted and sentenced in secret -- if at all -- and appear to have been arrested for future use as bargaining chips.

The deal leaves American citizen Siamak Namazi , who was arrested in October, in prison. And it doesn’t provide answers about Robert Levinson, the American CIA contractor who disappeared in 2007.

Kerry sees the prisoner deal as a positive precedent for Levinson's and Namazi's cases. Iran pledged in a written agreement to maintain an open line of communication about Levinson's case and assist in the search for information about his whereabouts.

Kerry credits the nuclear deal with showing that Iran and the U.S., despite having no formal diplomatic ties , can work together to resolve issues peacefully. “Were it not for that process, I do not believe this could’ve happened, nor do they,” he said, referring to the Iranians. 

According to Kerry, Zarif suggested that there was room for the two countries to work cooperatively on other issues, including in Yemen and Syria, where the U.S. and Iran are effectively fighting on opposite sides of proxy wars.

“I put a big ‘Who knows?’” Kerry said of that suggestion. “But you have to begin somewhere. And this is the beginning.”