

Azadeh Fattahi, an Iranian national who earned her PhD in Canada, had offers for postdoctoral positions in the US and Europe. President Trump’s executive order made the choice for her: She will join a cosmology group in the UK this fall. Credit: Fattahi

Ehsan Moravveji was excited at the prospect of returning to the Kavli Institute for Theoretical Physics in Santa Barbara, California. A postdoc in Belgium, he was scheduled to present an invited talk this month on massive stars. “In my current phase of career development, this counts a lot,” he says. “This is the hottest and most prestigious conference of the year I could attend.”

But his opportunity vanished on 27 January, when President Trump issued an executive order restricting people from seven countries from entering the US. Those countries include Iran, where Moravveji is from.

The original order unleashed chaos for travelers and prompted legal challenges; the courts suspended it 13 days later. On 6 March, Trump issued a new executive order on “protecting the nation from foreign terrorist entry.” (Several states reportedly plan to challenge the new order.) Iraq is no longer on the list of restricted countries, but the other six remain: Iran, Libya, Somalia, Sudan, Syria, and Yemen. The new order exempts holders of green cards and valid visas, and it removes the indefinite ban on Syrian refugees.

Although some of the hard edges have been filed down in the revised travel ban, the chill remains, including for scientists. Students and scholars from the affected nations who are already in the US worry that if they leave this country for conferences or collaborations—or to visit their families—they may not be able to get back in. Those who had hoped to come study and work in the US are now looking elsewhere. Scientists around the world and many professional societies are condemning the travel restrictions.



Secretary of State Rex Tillerson delivers remarks on the revised executive order on 6 March.

Even for those who have valid visas, travel can be humiliating. Entry is often at the discretion of border officials, and news outlets have reported that travelers have been asked to unlock cell phones or present their Facebook accounts. People from majority-Muslim countries not on the list, as well as from Mexico and elsewhere, are also skittish about traveling. One US-based, green card–holding Mexican faculty member says he canceled plans to attend a conference in Europe to avoid possible problems at customs on reentry.

In solidarity with those who can’t enter the US due to the travel restrictions, more than 600 scientists have pledged that they “will not attend US conferences until our colleagues can.” Till Sawala, a German astrophysicist at the University of Helsinki in Finland, started the boycott with friends. “We can show that we will not let our community be divided,” he says. “The other message is to those who are affected: We will not let you stay out in the cold on your own.”

Carlos Frenk, a cosmologist at Durham University in the UK, says he has offered postdoc positions to three Iranian scientists who normally might have gone to the US. “They wouldn’t consider it now,” he says. “They feel unwanted.” One of his new hires is Azadeh Fattahi, who also had offers in the US and Europe. She is sad that the choice was taken from her, and she says she no longer sees the US as a welcoming place for immigrants. “I might not consider the US for future plans,” she says.

Despite the benefit to his own research group, Frenk is upset about the ban. “This goes against everything that the US has stood for,” he says. “The ban is shortsighted and counterproductive. Science flourishes thanks to immigrants. To impose restrictions is ridiculous.”



Doctoral student Mehdi Rezaie has taken data on the 4 m Mayall Telescope at Kitt Peak in Arizona. Due to the executive order, the Iranian national has decided to pursue his PhD elsewhere once he earns his master’s from Ohio University. Credit: Rezaie

Iranians make up the largest group of scientists in the US from the affected countries. There are about 12 000 students in the US from Iran and 5000 from the other six countries originally singled out, according to Hadi Ghaemi, founder and director of the New York City–based Center for Human Rights in Iran. He worries that the travel restrictions, temporary for now, will drag on. It’s already difficult for an Iranian to obtain a US visa, he says, and there is no cooperation among governments to screen applicants.

Professional science organizations large and small have publicly objected to the travel restrictions, including 164 that signed a letter that was sent to the White House on 31 January. Rush Holt, the CEO of the American Association for the Advancement of Science and a former senator, released a statement shortly after the release of Trump’s revised order: “We are concerned that the executive order announced March 6 may be implemented in a manner that will continue to restrict travel to the United States and negatively impact students and scientists who seek to work and collaborate with their peers in the United States.”

Holt adds in an interview that science benefits the economy and the quality of life of all Americans. “If we want science to thrive,” he says, “we have to make sure there is freedom of communication, collaboration, and freedom to have diverse research teams.”

Ellen Weiss, the director of policy and communications at the 9000-member Biophysical Society, calls the executive order “very detrimental.” Travel is important, she says: “Scientists get something out of meeting face-to-face. The ban negatively impacts scientific progress. And it hurts the US’s reputation in the science world.”

Editor’s Note, 13 March: The article was corrected to reflect that about 17 000 total students, not just science students, from the seven affected countries study in the US.