California National Guard soldiers have been assisting Border Patrol agents in apprehending unauthorized immigrants near the U.S.-Mexico border, according to court filings.
The California National Guard arrived at the border in May to support border agents in combating transnational crime, like criminal gangs, human traffickers and illegal firearm and drug smugglers. Upon agreeing to assist federal officials at the border, Gov. Jerry Brown stated that the state’s National Guard personnel would not be enforcing immigration laws.
“But let’s be crystal clear on the scope of this mission,” Brown wrote in a letter  to Homeland Security Secretary Kirstjen Nielsen and Defense Secretary James Mattis in April. “This will not be a mission to build a new wall. It will not be a mission to round up women and children or detain people escaping violence and seeking a better life. And the California National Guard will not be enforcing federal immigration laws.”
But the line between guarding against transnational crime and enforcing immigration law is murky.
In two cases in which federal prosecutors charged someone with a misdemeanor for illegally entering the country, court documents describe California National Guard soldiers playing a role in apprehending unauthorized immigrants.
“On 08/01/2018 at approximately 0645 hours I was assigned to operate the Mobile x-ray to scan Hazmat shipments that come in form Mexico,” wrote one Customs and Border Protection officer in an incident report  describing his interactions with Border Patrol before the arrest of several people, including Mexican citizen, Jose de Jesus Gutierrez-Limon . “A National Guard soldier standing outside of the Mobile informed me that there were several people running North from Mexico.”
A Border Patrol agent arrived on the scene and the CBP officer informed him of the group and the direction they had run in, according to the report.
In the complaint  for another individual, Mario Alberto Estrada-Lorenzo, a National Guardsman also alerted Border Patrol to his presence before his arrest.
The Border Patrol agent who arrested Estrada-Lorenzo was notified by a National Guardsman who was operating a remote video surveillance that two individuals were heading north through the secondary border fence in an area about two miles west of the San Ysidro Port of Entry. The National Guardsman “guided” the agent to the two individuals, according to the statement in the complaint.
Estrada-Lorenzo’s defense attorney, Roxana Sandoval of the Federal Defenders of San Diego Inc., which handles much of the federal criminal pro-bono legal defense in the Southern District of California, raised the issue of the National Guard’s involvement to Magistrate Judge Jill Burkhardt.
“Mr. Estrada was arrested on Aug. 2, with the help of a National Guardsman, Specialist Fernando Garcia, and I would like to move to dismiss based on the fact that the National Guard’s involvement in his arrest violates the Posse Comitatus Act, which forbids the use of military personnel in the enforcement of the law,” Sandoval said in court.
The Posse Comitatus Act is a federal statute that restricts the use of the military in civilian law enforcement .
Burkhardt said Sandoval would need to submit a written brief to consider the motion.
But Estrada-Lorenzo decided to plead guilty that day, and the issue was never considered by the judge.
Lt. Col. Thomas Keegan, the California National Guard’s director of public affairs, said that National Guard forces operating under state authority are exempt from Posse Comitatus Act restrictions.
In response to separate Voice of San Diego requests to Gov. Jerry Brown’s office and the California National Guard, Keegan provided this statement: “The California National Guard continues to carry out its specific mission on the Southwest Border, which is to assist and support our federal partners in combating transnational criminal organizations by thwarting the illegal flow of money, weapons and controlled substances throughout the region. These activities include counterdrug surveillance, intelligence gathering, camera monitoring, paralegal work, telecommunications equipment installation and maintenance, heavy equipment operation, physical infrastructure maintenance, and administrative and logistical assistance.”
Brown wrote in his April letter, “Here are the facts: there is no massive wave of migrants pouring into California. Overall immigration apprehensions on the border last year were as low as they’ve been in nearly 50 years (and 85 percent of the apprehensions occurred outside of California).”
But the state’s border, particularly San Diego’s ports of entry, has become one of the largest gateways of hard drugs  along the U.S.-Mexico border.
In June, several states pulled National Guard troops  from the border in light of the family separations happening under the Trump administration’s zero-tolerance policy. California did not.