People seeking asylum at the U.S. border with Mexico will no longer be released in the United States and will instead be forced to wait in Mexico under a policy announced Thursday that marks one of the most significant moves by President Donald Trump to reshape the immigration system.

The measure is an aggressive response to a large and growing number of Central American asylum seekers, many of them families, who are typically released in the United States while their cases slowly wind through clogged immigration courts. It does not apply to children traveling alone or to Mexican asylum seekers.

Critics, including some legal experts, said migrants would be unsafe in some Mexican border towns and said the U.S. was illegally abandoning its humanitarian role, hinting at a legal challenge against a backdrop of previous courtroom setbacks for Trump on immigration.

We dive into the legality of the move, as well as its repercussions.

With files from the Associated Press.

Guests:

Jan C. Ting, professor of law at Temple University in Philadelphia, Pennsylvania; he was the assistant commissioner of the Immigration and Naturalization Service of the US DOJ from 1990-1993

Kennji Kizuka, senior researcher and policy analyst whose focuses include refugee issues at Human Rights First, a human rights organization based in Los Angeles, New York and DC