Havana—“Thank you for joining us at this truly historic moment as we prepare to raise the flag…symbolizing the restoration of diplomatic relations after 54 years,” then–Secretary of State John Kerry stated as he presided over the reopening of the US embassy in Havana in August 2015. After two dynamic and dramatic years of normalization, which have brought an unprecedented degree of bilateral cooperation, economic interaction, and travel, Kerry’s successor, Rex Tillerson, has begun the process of shuttering the embassy once again.

On September 29, Tillerson announced that he would reduce embassy personnel in Havana by 60 percent, effectively closing the consulate that provides visas to Cubans traveling to the United States and terminating all but emergency services for US visitors to the island. The State Department also issued a “Cuba Travel Warning,” advising citizens “to avoid travel to Cuba”—even as it conceded that “we have no reports that private U.S. citizens have been affected” by a mystifying pattern of health ailments that have struck members of the US and Canadian diplomatic community in Havana.

“Over the past several months, 21 U.S. Embassy employees have suffered a variety of injuries from attacks of an unknown nature. The affected individuals have exhibited a range of physical symptoms, including ear complaints, hearing loss, dizziness, headache, fatigue, cognitive issues, and difficulty sleeping,” reads the Tillerson press release, titled “Attacks Taken in Response to Attacks on U.S. Government Personnel in Cuba.” The release continues, “Until the Government of Cuba can ensure the safety of our diplomats in Cuba, our Embassy will be reduced to emergency personnel in order to minimize the number of diplomats at risk of exposure to harm.”

The travel advisory and the severity of the embassy reductions have set off alarms that the Trump administration has begun a concerted rollback of the Obama-initiated rapprochement. Although the State Department affirmed that “we maintain diplomatic relations with Cuba, and our work in Cuba continues to be guided by the national security and foreign policy interests of the United States,” suspicions abound that the White House is catering to the political interests of Florida Senator Marco Rubio, who has been working behind the scenes to revert US Cuba policy to the aggression of the Cold War. Last week, Rubio demanded that the Trump administration further punish Cuba by expelling more than half of the staff at the Cuban Embassy in Washington. He appears to have Trump’s ear. On October 3, the State Department sent a diplomatic note to Cuba ordering some 15 members of the Cuban embassy to leave Washington in the next seven days.

A Foreign-Policy Whodunit

There was a “big problem” in Cuba, President Trump explained to reporters in impromptu comments on the embassy drawdown; the Cubans, he claimed, “did some very bad things.”

In fact, Trump administration officials firmly believe that the Cuban government is not culpable for the “attacks”—though it’s not clear the health problems were actually caused by such an event—and have carefully avoided accusing Cuba of generating them. Their assessment appears to be based on intelligence intercepts of conversations among high-level Cuban officials after the United States brought the disturbing pattern of health problems among US and Canadian embassy personnel to their attention last January. As a “former senior American official” told The New York Times, “there was information that the Cubans were rattled by what had happened and were desperate to find the cause.”

That assessment was supported by the actions of Cuban President Raúl Castro. Last February, during a reception in Havana for a congressional delegation led by Senator Patrick Leahy, Castro pulled the head of the US embassy, Jeffrey DeLaurentis, aside and emphatically told him that Cuba had no knowledge of, nor any role in, the health problems among the US diplomatic corps. Castro pledged Cuba’s full cooperation in identifying the cause of the mysterious maladies, and even invited the FBI to come to Havana to investigate, as two officials with knowledge of the conversation told The Nation. “You have to cooperate with us, you have to cooperate with us” to resolve this problem, Castro urged DeLaurentis.

Since then, a team of FBI investigators has traveled to Havana at least three times—in June, August, and September—conducting their own forensic analysis in the search for a culprit and/or cause. To date, the FBI “has nothing that points to anyone,” as one Senate staffer whose office has received classified briefings summed up progress in the investigation. In Tillerson’s September 29 statement, the secretary of state conceded that “investigators have been unable to determine who is responsible or what is causing these attacks.”

US officials have told the Cubans that they suspect the health problems were the result of some sort of targeted “sonic attack”—a phrase the media have seized on—perhaps conducted by a third country. But that theory has been challenged by the medical and scientific community, as well as former members of the intelligence community. Doctors and psychoacoustics experts consulted on the case have stated that the wide variety of symptoms is unlikely to have been caused by any known sonic or surveillance device. “No one has a device that could do this. Because no such device exists,” says Fulton Armstrong, a retired CIA officer who worked on Cuba policy in the Clinton White House. The idea that agents of a third country, like Russia or North Korea, could “lug special ray-gun technology around Havana, aim it at diplomats’ homes and tourist hotels undetected and unfettered, and get away with it all,” according to Armstrong, appears equally implausible.

The investigation has been shrouded in secrecy, compounding the mysterious nature of these health problems. None of the 21 “members of the Embassy community,” as State Department press officials describe the affected personnel (some were intelligence agents in Cuba working under cover as diplomats), have identified themselves or spoken out publicly on the issue. Nor has the FBI formally released any of its preliminary findings. The Royal Canadian Mounted Police, who are also investigating what happened to several members of their diplomatic staff in Havana, have remained silent. Cuban authorities who are actively investigating the crisis have yet to release formal reports on what they have, or have not, found.

The lack of transparency has fostered conspiracy theories and widespread speculation. In Cuba, for example, one of the leading political columnists, Fernando Ravsberg, has accused the CIA of mounting “un “Maine acústico,’” or “an acoustic Maine”—a reference to the 1898 sinking of the USS Maine in Havana Harbor by an unexplained explosion, which was used by US warmongers to swing public opinion in favor of military intervention during Cuba’s fight for independence from Spain. According to Ravsberg, the “sonic attacks” are a CIA psychological operation designed to set the stage for yet another US invasion.

Such theories have the capacity to increase tensions further between Washington and Havana and sabotage the progress in reconciliation that has been made since December 17, 2014, when Raúl Castro and President Obama announced a breakthrough in relations. And that may well be the intention of the whole operation, if indeed the health problems are the result of a dirty-tricks department of an as-yet-unidentified country or entity. Ben Rhodes, the former deputy national-security adviser who was chief architect of Obama’s successful rapprochement efforts, tweeted that “The Trump Administration is playing right into the hands of perpetrators who want to harm US-Cuba ties.” “Whoever is responsible for the attacks on US diplomats in Havana—if it was an intentional act—did it in order to damage US-Cuban relations,” says American University professor William LeoGrande. “The Trump administration’s disproportionate response hands them a victory.”

The Fallout

In a clear effort to keep this diplomatic crisis from escalating further, the Cuban government has reacted with relative restraint. Initially, Josefina Vidal, the Foreign Ministry official in charge of US affairs, called Tillerson’s decision “hasty” and reiterated that Cuba would continue to cooperate in the investigations to determine what, or who, caused these maladies. On October 3, Cuban Foreign Minister Bruno Rodriguez held a press conference in Havana to reiterate “that Cuba has never perpetuated, nor will it ever perpetuate, attacks of any sort against diplomatic officials or their relatives.” The foreign minister urged the Trump administration “not to continue politicizing this matter, which can provoke an undesirable escalation and would [further] reverse even more bilateral relations.”

Average Cubans, who now face a de facto US immigration ban since the US consulate is no longer processing visa applications—and who will take an economic hit if US visitors are scared away by Trump’s travel advisory—have been even more vocal. “Just as the re-establishment of Cuba-US relations was a positive influence, now this will be very negative,” one Cuban who rents out an apartment through Airbnb told a Reuters reporter. Three of his renters have already canceled since September 29. Trump’s decisions, he said, “are creating a mood of insecurity for those who want to travel to Cuba.”

“The United States must prioritize the safety of our diplomats serving overseas. At the same time, this must be balanced with policies that serve US national interests, such as a functioning US embassy in Havana and travel in both directions,” said Collin Laverty, who runs Cuba Educational Travel, one of the leading travel providers to the island (CET has helped coordinate The Nation’s Cuba trips). As tour companies like Laverty’s CET field a flood of calls from anxious travelers about whether it is safe, and still legal, to go to Cuba, the industry is leading the pushback against Trump’s decision. Major airline carriers such as American and United, which initiated direct commercial flights to Cuba a year ago and have ferried almost half a million US citizens to the island this year, have publicly declared that their transportation services will continue unchanged. So have the travel providers. “We believe that its decision is unwarranted, and we are continuing to organize travel to Cuba and encourage others to do so,” said Bob Guild, vice president of Marazul Charters and head of a recently formed association of over 100 travel providers known as Responsible & Ethical Cuba Travel (RESPECT).

“Cuba continues to be one of the safest places in the world for visitors,” Laverty emphasizes. Out of the tens of thousands of travelers that have gone to Cuba under the auspices of CET, he says, there have been no reports of any such incidents affecting their health.

But perhaps the most significant, and courageous, voice for maintaining normal diplomatic relations comes from the diplomatic corps—the very people whom the Trump administration claims to be trying to protect. As the health crisis evolved this year, diplomats posted at the US embassy have resisted leaving; instead, they have let it be known that they want to stay. “It’s a complicated question regarding what is actually causing the health issues in Cuba, but our members are clear that they have a mission to do,” the president of the American Foreign Service Association, Barbara Stephenson, said in a strong statement opposing the embassy drawdown.

Stephenson made it clear that she was “speaking on behalf” of the US embassy community in Havana. To conduct diplomacy, she said, US diplomats “need to remain on the field and in the game.”