CREW files historian amicus brief in support of California’s effort to block National Guard deployment to Los Angeles
The Ninth Circuit Court of Appeals should affirm the Northern District of California’s temporary restraining order blocking President Trump from deploying National Guard troops to Los Angeles, according to an amicus brief filed by CREW on behalf of University of Maryland law professor and legal historian, Mark A. Graber.
In June, President Trump ordered the deployment of around 4,000 California National Guard troops to Los Angeles in response to protests against the Trump administration’s immigration raids and deportations. Trump claimed the protests constituted a “rebellion” and that he was unable to execute the laws of the United States. On June 9, 2025, California Governor Gavin Newsom sued the Trump administration for federalizing and deploying the California National Guard in Los Angeles, on the basis that these conditions were not met and arguing that the deployment violated the 10th Amendment and the Posse Comitatus Act which prohibits using military forces to engage in domestic law enforcement in most cases. The district court issued a temporary restraining order, which the Trump administration appealed to the Ninth Circuit.
The amicus brief argues that “the President’s extraordinary actions find no support in American history or judicial precedent.” America’s founders opposed military involvement in domestic affairs, except under extreme circumstances. The Militia Act of 1903, the statutory predecessor to the law that Trump cites, was historically understood to authorize the president to federalize state militias in response to war or warlike conditions. Those conditions—invasions, rebellions, and uprisings that render the courts inoperative—were not met by the largely peaceful protests in Los Angeles. History also confirms that the courts have the authority to determine whether those conditions are met. As the brief states, “Supreme Court decisions from the nineteenth century emphatically rejected the notion of unreviewable presidential discretion to deploy the military on American soil, dismissing the argument as repugnant to our founding principles.”
Given the lack of legal justification for the Trump administration’s federalization of the California National Guard, the Ninth Circuit should affirm the district court’s temporary restraining order and block Trump’s deployment of National Guard troops in Los Angeles.