Trial set to test whether Trump broke 1878 ban on military policing

A San Francisco district judge has scheduled a trial to begin Aug. 11 to determine whether the Trump administration violated an 1878 law that bars the use of military forces for domestic law enforcement.

During the three-day trial, Senior U.S. District Judge Charles R. Breyer will consider whether the deployment of the California National Guard -- federalized by President Donald Trump -- and U.S. Marines to assist in immigration enforcement in Los Angeles County violated the Posse Comitatus Act.

Breyer's decision to hold a trial will test the scope of the act, passed by Congress shortly after Reconstruction, and is extraordinary because it pits a president against a state governor.

"Pursuant to Federal Rule of Civil Procedure 65(a)(2), the Court will advance the trial on the merits and consolidate it with the preliminary injunction hearing, which the Court sets for August 11-13, 2025," Breyer wrote in a Wednesday night order. "The Court will not entertain requests or stipulations for extensions of time." Newsom et al. v. Trump et al., 25-cv-04870 (N.D. Cal., filed June 9, 2025).

"There has never been a [Posse Comitatus] case where the governor is suing the president before," said Los Angeles attorney Allan L. Dollison, who served as a California National Guard officer during the 1992 riots in the city following the violent arrest of Rodney King.

Breyer also ordered that the California attorney general's office may take the deposition of Ernesto Santacruz Jr., the field office director of the Los Angeles Office of the Department of Homeland Security.

Gov. Gavin Newsom sued President Donald Trump on June 9, arguing that the president's federalization of the National Guard was illegal.

Breyer granted a temporary restraining order in the governor's favor, concluding that the president's actions violated the 10th Amendment.

But a 9th U.S. Circuit Court of Appeals panel reversed the judge on June 19, allowing Trump to maintain control of the National Guard to help protect immigration officers and federal buildings in Los Angeles County on the grounds that its judicial review of the president's action must be "highly deferential."

Neither Breyer nor the 9th Circuit panel -- comprised of Judges Mark J. Bennett, Eric D. Miller and Jennifer Sung -- addressed a possible violation of the Posse Comitatus Act, but the judge ordered expedited discovery on that issue on June 25.

The U.S. Department of Justice objected to the state taking Santacruz's deposition, arguing that he does not direct military operations or the National Guard.

But Breyer, noting that Santacruz already has submitted two declarations in the case, ruled that he must be deposed during the week of July 21.

The judge wrote in Wednesday night's order, "Defendants themselves offered up Mr. Santacruz on the subject of what the federalized National Guard and U.S. Marines are doing in Los Angeles, which is directly relevant to whether Defendants have violated the Posse Comitatus Act."

Federal immigration officers and U.S. Marines have remained in the Los Angeles area. On Monday, agents in tactical gear marched through MacArthur Park, some on horseback, over the objections of Newsom and Los Angeles Mayor Karen Bass.

Attorneys representing defendants in criminal cases have cited alleged Posse Comitatus Act violations, often in motions to suppress evidence, that have usually been decided in favor of the government.

In 1975, U.S. District Judge Andrew W. Bogue of the District of South Dakota issued a ruling in a criminal case against defendants accused of obstructing law enforcement officers at Wounded Knee, South Dakota.

The government sought to exclude evidence of military involvement in the standoff. Bogue, however, ruled that the use of "Army or Air Force troops, one soldier or many, in an active role of direct law enforcement by performing one or more of the specific acts set forth above during the occupation of Wounded Knee, is admissible."

But the use of Army or Air Force equipment, supplies, or materiel, or personnel who performed a "passive role" that might have "indirectly aided law enforcement officers" was not admissible at the trial, Bogue added. U.S. v. Red Feather, 392 F. Supp. 916 (D. S.D. 1975).

In 2015, a 9th Circuit en banc panel overturned a three-judge panel decision, with Senior Judge Marsha S. Berzon changing her mind, about whether evidence obtained by a U.S. Navy intelligence agent should be suppressed in a child pornography conviction because of an alleged violation of the Posse Comitatus Act. U.S. v. Dreyer, 2015 DJDAR 12083 (9th Circ., filed March 25, 2013).