New Delhi, Aug. 29 -- On May 28th Art Lussi received an alarming message. His hotel, the Grandview Lake Placid, in a mountain resort in upstate New York, was halfway through a 150-room renovation ahead of the summer rush. But that morning Immigration and Customs Enforcement (ICE) agents had detained a Venezuelan maintenance worker (with legal status), plus 20 contractors. Mr Lussi estimates that the resulting delay, of nearly a month, cost half a million dollars in lost business. In a town already short of workers, finding replacements was nearly impossible. "We could still use 20 more people right now," he says.

Donald Trump promised a draconian crackdown on immigration and has largely kept his word. Since his return to office, America'...