Even before the Supreme Court ruled Thursday that Trump has broad power to deport hundreds of thousands of migrants living legally in the U.S. under temporary protected status, David Bier feared the U.S. was slipping toward a demographic cliff.

“We’re destined to be there, in short order, there’s no question,” Bier said. “We’re already seeing a situation where most counties in the United States had more deaths than births.”

An expert on population and immigration at the libertarian Cato Institute, Bier believes the U.S. is beginning to look more like China, Italy and South Korea. Those nations face rapid aging and population decline.