Tehran has a long history of arbitrarily imposing new sentences upon political prisoners to prevent their release while applying additional psychological pressure. In other cases, prison authorities decline to release detainees on their appointed dates. 

Nazanin Zaghari-Ratcliffe‘s likely status as a hostage has been highlighted on many occasions by her husband, her other advocates, and other critics of the Iranian regime. Furthermore, Iranian authorities themselves had validated that description by explicitly linking her case to the future repayment of debt for military sales that the British government had owed to Iran since before the 1979 revolution that brought the Islamic Republic to power. High-ranking Iranian officials, like Foreign Minister Javad Zarif, have confirmed their hostage-taking strategy. They have floated the idea of exchanging persons, like Zaghari-Ratcliffe, for Iranians who have been detained in the UK, the United States, and elsewhere based on legitimate crimes ranging from sanctions violations to terrorism.

The number of foreign nationals currently detained in the Islamic Republic may be much higher than the half dozen that are widely recognized. This lack of information makes it difficult to assess what the Iranian government had in mind when its spokesperson, Ali Rabiei, said recently: “There is nothing new about the exchange of prisoners. We are ready to exchange all the prisoners. If this has not happened so far, it is because of the unpreparedness of the U.S. government.”

Rabiei specifically addressed renewed political pressure over American hostages, which emerged from the Biden White House on the 14th anniversary of former FBI agent Robert Levinson‘s disappearance. After more than a decade of demanding answers from the Iranian government about Levinson’s whereabouts, his family announced last year that the US government had determined he was no longer alive. This assessment remains unchanged. The Biden administration has now made it clear that the U.S. continues to hold Iran responsible and remains unsatisfied with their explanations regarding what occurred after he was last seen on Kish Island.

In a statement, Secretary of State Antony Blinken explicitly connected Levinson’s case to those of at least four American citizens detained on spurious charges in the Islamic Republic. “We call on the Iranian government to provide credible answers to what happened to Bob Levinson and to immediately and safely release all US citizens who are unjustly held captive in Iran,” he said.

While the Biden presidency appears to be more akin to its European allies than its domestic predecessor in its praise of diplomacy and open communication lines, Blinken’s statement nevertheless accompanied the imposition of new sanctions. These sanctions narrowly targeted two IRGC interrogators accused of human rights abuses in the wake of recent mass protests in Iran.

Blinken implied that these would not be the only measures to support the Iranian people’s rights or wrongfully imprisoned foreign nationals. “We will continue to consider all appropriate tools to impose costs on those responsible for human rights violations and abuses in Iran,” the statement said. Tehran’s critics are expected to watch closely to see whether Biden follows through on this promise and whether his European allies follow suit.

Around the same time the news broke regarding the end of Zaghari-Ratcliffe’s sentence, British citizen Kylie Moore-Gilbert spoke to the media about the more than two years she served as a hostage in Evin Prison, underscoring the situation. The University of Melbourne Professor of Islamic Studies, who also holds Australian citizenship, was arrested after having been invited to a conference by Tehran University. Promptly, she was sentenced to 10 years in prison on baseless charges of espionage. Last November, her early release came about as a result of a prisoner swap, the details of which were heavily skewed in Iran’s favor. Authorities arranged for her release to coincide with that of three terrorists who were serving sentences in Thailand over the February 2012 bombing intended to kill Israeli diplomats.

Moore-Gilbert’s case coincided very closely with the Iranian regime’s effort to secure release for its terrorists. In November, Iranian authorities moved the Iranian-Swedish academic Ahmadreza Djalali into solitary confinement as preparation for implementing his capital sentence. The move was motivated by the fact that a court in Belgium, where Djalali had also resided and worked, was then beginning formal prosecution of Assadollah Assadi, an Iranian diplomat accused of masterminding the attempted bombing of an Iranian opposition gathering near Paris.

Assadi was ultimately convicted and sentenced to 20 years in prison on February 4, while Djalali has thus far avoided the gallows in the wake of Belgian authorities threatening to retaliate by severing ties with Iran if the execution were carried out. Still, Djalali has remained in solitary confinement and denied fundamental rights and family visits while his health deteriorates. As with Zaghari-Ratcliffe, Iranian authorities most likely believe that escalating pressure on this prisoner could still make him valuable to pursuing prisoner swaps or other benefits.

The Djalali and Moore-Gilbert cases are also linked to Tehran’s efforts to turn them into assets against foreign adversaries. In her interview on Tuesday, Moore-Gilbert noted that the Islamic Revolutionary Guard Corps tried “many times” to coerce her into agreeing to serve as an Iranian spy in exchange for her release. Similarly, Djalali said that his conviction on charges of spying for Israel came about only after being pressured to spy for Iran and refusing.

Moore-Gilbert also explained that her case remained unknown to the general public for longer than she preferred. Her family complied with pressure from both sides of the issue, suggesting that public notoriety would only interfere with diplomatic talks aimed at securing her release.