Trump’s travel ban is already stopping scientific collaboration

On Friday, President Donald Trump signed an executive order that denies Syrian refugees entry to the US, suspends all refugee admissions for 120 days, and blocks citizens of seven countries from entering the US for at least 90 days. Those affected by the travel ban include scientists, some of whom are speaking out about how the order will affect their work and the broader scientific community.

“While one can understand security imperatives, a broad ban that restricts movement of widely defined groups can hold back important scientific progress; progress that can solve some of our most urgent problems,” says one professor at a leading US university. A dual citizen of one of the countries on the list, he says he will probably have to cancel academic and research trips scheduled for the next few months, as well as a planned visit to see his mother.

The countries targeted by the ban are Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen, all of which have majority Muslim populations.

A professor at a university in the New York area says his department includes some...