Academics say they are increasingly wary of travelling to conferences in the US after a French scientist was deported over text messages critical of Donald Trump’s cuts to research funding – an incident that reinforces the case for a boycott of American academic meetings, some argue.

The concerns over US travel come after a space science researcher from the French National Centre for Scientific Research (CNRS) was detained at Houston airport on his way to the (LPSC), a gathering of about 2,000 international scientists held from 11 to 15 March.

Selected for a search by border guards, the scientist was asked to unlock his mobile phone and laptop, where messages discussing Trump’s treatment of scientists were found.

Those messages, thought to concern the US president’s cuts to federal funding, were deemed “hateful” and “conspiratorial”, a source told Le Monde newspaper. The researcher was accused of demonstrating “hatred toward Trump”, which could be “described as terrorism” and was deported back to Europe the next day.

̽����Ƶ

The incident, which took place on 9 March, has led to , who said the deportation related to “a personal opinion on the Trump administration’s research policy”.

“Freedom of opinion, free research, and academic freedom are values ​​that we will continue to proudly uphold,” added Baptiste, who said he would “defend the right of all French researchers to be faithful to them, while respecting the law”.

̽����Ƶ

The incident has caused some European scientists to reconsider their travel plans ahead of this spring’s busy American academic circuit.

Space scientist Mark Wieczorek, director of research at the Institut de Physique du Globe de Paris, part of CNRS, said the situation was “very troubling” and, despite being a dual US-French citizen, he now would “only go to the US for the case of a family emergency”.

“I was likely on the same plane as the person who was stopped, going to the same conference,” said Wieczorek, who is also affiliated to Université Paris Cité.

“I have talked to many people, and the opinions range from mine to ‘I’m going to need to think about this before deciding to go to a US conference’ to ‘What choice do we have as a young researcher who is just getting started?’” he added.

Given the French scientist in question is a “permanent researcher employed by CNRS”, it is “unlikely that this person is a radicalised terrorist and it is unlikely that their hatred of Trump is greater than mine as a US citizen,” continued Wieczorek on the supposedly derogatory statements discovered on the individual’s devices.

“If these statements are later found not to be death threats, then this is a clear violation of the freedom of speech principles that are enshrined in the US constitution and the French Declaration of the Rights of Man and of the Citizen which was written at about the same time,” he said.

Marc Veldhoen, professor of immunology at the University of Lisbon, said the deportation had highlighted the increasingly harsh treatment of foreign nationals – including a  – arrested and detained over visa irregularities.

̽����Ƶ

“We would not have thought this was possible only two to three months ago,” said Veldhoen on his concerns for “colleagues and friends in the US”.

̽����Ƶ

“The situation was already uncertain for those not holding US nationality or a green card after the election. Now it seems worse than anticipated, and it is a concern,” he said.

Given the “circumstances as they are now”, Veldhoen said he “would be concerned” about sending colleagues to the US, where his lab has established collaborations, despite previously viewing US-Europe as the “backbone of international [scientific] cooperation”.

“It can still be an incident from an overzealous official, but the uncertainty has grown sufficiently to advise against travel to the US,” he said, adding that this “also applies to conferences in the US” and suggesting it may “be possible to move some events to Canada or the EU”.

Other scholars expressed similar trepidation on social media, with one Norway-based scholar saying he was “genuinely worried” about travelling to the US later this year. A Dublin-based astrophysicist said the incident was the “latest demonstration that the US is now a hostile environment for science and scientists”. He would be “very hesitant” to attend any event in the US, he added.

Nathalie Grandvaux, professor in the department of biochemistry and molecular medicine at the University of Montreal, said the incident reinforced her view that international scholars should boycott the US – a call made initially in relation to Trump’s wish to annex Canada.

“Attending international conferences represents a significant financial investment. Given the current context, I do not see justification for these funds to contribute to an administration that undermines both democratic and scientific integrity values,” said Grandvaux, adding that she would not risk the “safety of my team members” given the recent actions of border officials.

Ironically, Trump’s own science policies are more likely to halt academic conferences rather than any boycott, remarked Paris-based Wieczorek.

“It is quite possible that the [next] LPSC conference will be cancelled – not because of travel bans but because the administration is discussing a 50 per cent cut to Nasa’s science budget which is used to partially fund this meeting,” he said.

̽����Ƶ

jack.grove@timeshighereducation.com