More than 1,400 economists from around the country have signed a letter to the Trump administration and congressional leaders, about the economic value of immigration.

They write, “immigration is one of America’s significant competitive advantages in the global economy. With the proper and necessary safeguards in place, immigration represents an opportunity rather than a threat to our economy and to American workers.”

Geovanni Peri is one of those economists. He’s chair of the Economics Department at the University of California, Davis, and studies the economics of immigration.