USCIS, Jan. 28, 2019
"SUBJECT: Guidance for Implementing Section 235(b)(2)(C) of the Immigration and Nationality Act and the Migrant Protection Protocols
Purpose This memorandum provides guidance to immigration officers in U.S. Citizenship and Immigration Services (USCIS) regarding the implementation of the Migrant Protection Protocols (MPP), including supporting the exercise of prosecutorial discretion by U.S. Customs and Border Protection (CBP). This memorandum follows the Secretary of Homeland Security’s January 25, 2019, memorandum, Policy Guidance for Implementation of the Migrant Protection Protocols."