The proposal calls for ad campaigns advising migrants in the U.S. to take their cases to court and fight deportation if detained. “The backlog in the immigration system is tremendous,” said former Foreign Minister Jorge Castañeda. The idea is to double or triple the backlog, “until [U.S. President Donald] Trump desists in this stupid idea,” he added.

Mr. Castañeda is part of a group of Mexican officials, legislators, governors and public figures planning to meet with migrant groups Saturday in Phoenix to lay out plans to confront the Trump administration’s deportation policy.

Mexico’s government hasn’t endorsed the strategy or the group’s Phoenix mission. But it recently allocated some $50 million to assist undocumented migrants facing deportation, and President Enrique Peña Nieto has instructed the country’s 50 consulates in the U.S. to defend migrants.