For weeks, President Donald Trump and Secretary of State Mike Pompeo have been claiming without evidence that the Covid-19 pandemic is linked to a lab in Wuhan that researches bat coronaviruses. Their efforts are clearly calculated to distract from Trump’s bungled response to the virus, and, for rational observers, they have tainted the notion that the outbreak began with a lab accident or safety breach.

But while many scientists think a lab origin is unlikely, biosafety experts still see it as a possibility. The administration’s posturing may ultimately make it much more difficult to figure out what actually happened in the earliest days of the outbreak — even if, ironically, the clues do end up leading back to a lab.

Based on the available evidence, SARS-CoV-2 — the virus that causes Covid-19 — likely emerged in bats in the wild and then jumped to humans, possibly via an intermediary animal. What is unclear is where that pivotal transmission, called a “spillover” event, occurred. Chinese authorities have pushed the theory that it happened at Wuhan’s Huanan Seafood Wholesale Market, where 27 of the 41 earliest cases were clustered. Some scientists believe it could have happened in nature, for example in the villages surrounding the caves in southwestern China where bats harboring coronaviruses live. As countries urbanize and humans encroach onto animals’ habitats, natural spillovers have become increasingly common. But other experts say that the possibility of a lab accident, infection during fieldwork, or other safety breach cannot yet be ruled out — and that determining whether such a breach occurred is imperative.

“An open investigation is absolutely warranted and absolutely essential,” said Richard Ebright, a professor of chemical biology at Rutgers University. A longtime biosafety proponent, Ebright believes that a lab error is “at least as probable” as an entirely natural spillover event. “Unsupported claims by Trump and Pompeo have politicized and polarized the issue and likely have had the effect of making an open investigation less likely.”

Last month, Australia led the way in calling for such an investigation, suggesting that it would raise the issue at the World Health Assembly, the decision-making body of the World Health Organization, at its meeting this week. “We just want to know what happened so it doesn’t happen again,” Australian Prime Minister Scott Morrison said at a press conference on May 8. Canada, Germany, and Sweden backed the idea. But U.S. meddling sabotaged the effort, and the result is a watered down resolution, backed by the European Union and over 100 countries, calling for an inquiry into the international response to the pandemic. The resolution avoids singling out China, and on Monday Beijing threw its support behind the weakened language. It was adopted on Tuesday, but the world will need to wait for a full investigation.

Such an effort is needed for many reasons. China has been conducting its own investigation but has not shared any information with the World Health Organization. And the Chinese government’s early cover-up of the outbreak and silencing of critics does not instill confidence that it will be forthcoming as to the origins of the virus.

Virologists say that learning more about how the coronavirus infected humans could help ward off future outbreaks. The discovery of an animal species carrying a closely related virus, for example, could help the world prevent a resurgence in cases by showing where to focus control efforts. A wet market origin could fuel an international movement to close wildlife markets. And for scientists, knowing whether a lab accident played any role is critical to ensuring safe research conditions going forward.

But by relentlessly pushing the lab leak theory without giving evidence to back it up, Trump and Pompeo have narrowed the chances that the world will get clarity on the pandemic’s origins. Both men have clouded the discussion by touting the conspiracy theory that the coronavirus was deliberately made in a Chinese lab as a bioweapon — an idea that has been roundly rejected by both scientists and intelligence officials. Trump has also called on China to compensate the United States for the outbreak. Pompeo, meanwhile, has so angered Beijing that on Monday, Chinese foreign ministry spokesperson Zhao Lijian called him a “lying blabbermouth.” By most accounts, the international push for an investigation came about not because of the extreme U.S. position, but in spite of it.

Speculation about the Wuhan Institute of Virology, a biosafety level 4 facility built with French assistance, started early on. In January, a study published by Chinese scientists in The Lancet found that the first patient diagnosed with the coronavirus, on December 1, had no connection to the wet market.

That set off guesses and conspiracy theories alike. “We need to look wider than just the wet market origin,” said Filippa Lentzos, a biosafety expert at King’s College London. “At the moment it’s still an open question.” The closest known relative of SARS-CoV-2 is a bat coronavirus that was sampled by the Wuhan Institute of Virology, but the two viruses are not close enough to suggest a direct link.

A number of recent outbreaks, including HIV, Zika, and the first SARS virus, were caused by purely natural spillovers. And yet, there have also been outbreaks caused by lab accidents. A 1977 outbreak of H1N1 in the Soviet Union and China is believed to have been caused by Soviet scientists experimenting with a live virus in a lab, perhaps to make a vaccine. In a 2007 breach at Pirbright, a biosafety level 4 animal research facility in Surrey, in the United Kingdom, wastewater containing live virus leaked out of drainage pipes and into the soil, sickening animals in the region with foot-and-mouth disease. The first SARS virus escaped from labs in Asia on three occasions. Even the U.S. Centers for Disease Control and Prevention laboratories — which are considered state-of-the-art — have experienced serious safety breaches.

The Wuhan Institute of Virology worked with U.S. collaborators on controversial experiments called gain-of-function studies, which involve making viruses more dangerous to test their transmissibility. Years before the onset of the Covid-19 pandemic, gain-of-function experiments were at the center of a global scientific controversy. Proponents said that the studies could help advance knowledge of infectious diseases and prevent the next pandemic. Detractors warned that they were too risky and that they might also cause the next pandemic. The National Institutes of Health placed a moratorium on such research in 2014 and lifted it in 2017 after developing a new review framework for the studies. Today, most gain-of-function research is funded by the United States.

In order to determine what happened, these experts say, the world needs a neutral inquiry untainted by the Trump administration’s efforts to divert attention away from the botched U.S. response. “The investigation shouldn’t be about apportioning blame,” said Lentzos. “The investigation needs to be about finding a credible answer for how the pandemic started and then using that to develop an early warning for the future.”

When Australia called for an inquiry in April, its government aimed to counter the Trump administration’s posturing with a more sensible proposal. The goal was “to minimize the reach of conspiracy theories about the virus that have been surfaced by U.S. and Chinese officials alike,” said Natasha Kassam, a research fellow at the Lowy Institute, a think tank in Sydney.

For years, Australia had been a loyal ally of the United States, backing American foreign policy goals even as the rest of the world balked. During the Iraq War, as the Bush administration pushed faulty intelligence about weapons of mass destruction, Australian Prime Minister John Howard was so pliant that commentators dubbed him Washington’s “deputy sheriff.” The Trump presidency has seriously tested Australia’s devotion, though. Pompeo tested it further when he suggested, following Australia’s announcement, that the country was merely supporting U.S. efforts to pinpoint an origin.

A “dossier” leaked to the Australian press caused further problems. The document, which was detailed by the Australian paper the Daily Telegraph in a breathless article published on May 4, dealt with China’s handling of the outbreak and cast suspicion on the Wuhan Institute of Virology. Many of the details were familiar, including the fact that China had silenced doctors, thwarted early attempts at international cooperation, and subjected academic papers on the virus to special review. It later emerged that the dossier was in fact a summary of existing news reports that is believed to have been circulated by the U.S. embassy in Canberra.

These developments annoyed Chinese officials, who last week threatened to place steep tariffs on Australian beef and barley. “They see it, through their dialectical lens, as a coordinated and direct attack by Australia on behalf of the United States,” said Andrew Chubb, an expert on Chinese politics and international relations at Lancaster University in the United Kingdom. Australia ended up backing down, and the Morrison government threw its support behind the milder World Health Assembly resolution. China imposed the tariff on barley and banned exports from four Australian meat processing plants anyway.

If a full investigation is eventually conducted, biosafety experts hope that it will include a review of samples and safety protocols from the Wuhan labs as well as the wet market. Simon Wain-Hobson, a virologist at the Pasteur Institute in Paris, said it would be useful to see lab records from Wuhan going back to August, as well as any records from work with other mammalian viruses.

“If it was a breach, we need to know, because then clearly we are overestimating our capacities to contain some of these viruses,” he said. “We need to know this as scientists because if it can infect one scientist then it can infect a third, fourth, fifth.”

The Trump administration’s determination to find a scapegoat is short-sighted, he said, and the notion of asking China to pay for the outbreak is unprecedented. “No country can pay retribution for a thing like this,” Wain-Hobson told The Intercept. “What about a bit of compassion?”

Correction: May 20, 2020
An earlier version of this article incorrectly stated that the NIH funded work at the Wuhan Institute of Virology through its PREDICT program. PREDICT is a program of the U.S. Agency for International Development.