Immigration advocates in Canada said the reasons for fleeing were more complicated: The president’s executive order in January on immigration that affected countries that are mostly Muslim was certainly a factor, but so were frustration with the immigration process in general and concern over anti-Muslim rhetoric.

Migrants have been coming to places like Roxham Road not because they want to sneak over the border; the expectation is to walk right into the arms of the Canadian authorities. An agreement between the United States and Canada makes it virtually impossible for them to ask for asylum at a legal border crossing; Canadian border officials would have to turn them back. But a technicality allows them to bypass the agreement by illegally setting foot in Canada.

“Once they get arrested, they’re already on Canadian soil,” said Jean-Sébastien Boudreault, the president of the Quebec Immigration Lawyers Association, “so we have to let them do a refugee claim.”