How can you tell if your new partners in an agreement can be trusted? One hint — if they try to kidnap some of your citizens as part of a prisoner swap, don’t expect them to be too eager to meet other milestones in the deal. The New York Times’ Peter Baker offers a gripping account of the Iranian attempt to seize Jason Rezaian’s family and keep them in Iran even as the US concluded the exchange that set the Washington Post reporter free:

Three of the freed Americans were to leave Iran on a plane operated by the Swiss, who had helped broker the prisoner talks and who represent American interests in Tehran, where there is no United States embassy. A fourth had already left on a commercial flight, and a fifth, who lived in Tehran, had chosen to stay.

But as Mr. Rezaian and the other two prisoners, Amir Hekmati and Saeed Abedini, were preparing to leave, no one could find Mr. Rezaian’s wife, Yeganeh Salehi, or his mother, Mary. Ms. Salehi, an Iranian journalist, hadbeen arrested with Mr. Rezaian in July 2014 before being released, and his mother had gone to Iran to be closer to her imprisoned son.

“They had disappeared,” said an American official, who along with others described the events on the condition of anonymity. “Nobody could find them, and they were not answering phones. The Iranians then said there were legal issues that would prevent either from leaving the country.”

Iranian officials tried to persuade the Americans and the Swiss to take the three prisoners and leave without Ms. Salehi or Ms. Rezaian. In Geneva, Brett McGurk, the lead American negotiator, refused, saying the deal had always included Mr. Rezaian’s family.

To get Rezaian’s two family members onto the plane, it took John Kerry demanding Iranian foreign minister Mohammed Javad Zarif to comply with the terms of the exchange. Even then, the Iranians continued to play hide-and-seek with Rezaian’s wife and mother. Three times they attempted to restrain the women and refuse to allow them to board the plane, creating a standoff that lasted for hours at the airport. Finally, after numerous attempts to welch on the deal, the Iranians allowed the two women to board the plane.

Baker suggests this shows that “parts of Iran’s factionalized system still strongly resist any rapprochement with the United States.” That’s certainly true, but Iran is an authoritarian state run by extremist mullahs. If they wanted this prisoner exchange to go off without a hitch, it would have. The IRGC would have ensured it, and anyone who balked would have found himself on the way to Evin to take Rezaian’s place. The Iranians wanted to humiliate the Americans, and test their resolve over a couple of people who they probably don’t particularly want around anyway.

With that in mind, what does that say about their intent to comply with the overall agreement to stop pursuing nuclear weapons, which they desperately want? The US barely could verify the release of two women as part of a prisoner swap. Can’t wait to see what Iran does with $150 billion in assets and plenty of time to use it.