Under the Constitution, Congress has the authority to specify when members of the state militias, today referred to as the National Guard, may be called into federal service. Exercising that authority, Congress set out specific criteria that must be met before presidents may federalize members of the National Guard. After President Trump deployed members of the California National Guard to Los Angeles in the wake of mostly peaceful protests, California and Governor Gavin Newsom challenged the legality of Trump’s actions in federal court. A district court granted temporary relief, finding that Trump’s decision was likely unauthorized by law. The Trump administration appealed that ruling, and in September 2025, CAC filed an amicus brief explaining why courts have the authority to review the legality of a President’s decision to employ the National Guard. 

The Trump administration maintains that under an 1827 Supreme Court decision, Martin v. Mott, courts cannot review a President’s determination that the statutory conditions for federalizing the National Guard are met. Our brief shows why that argument is wrong. 

As we explain, Mott held only that a militia member could not relitigate the outcome of his courtmartial by filing a civil lawsuit against the officers tasked with punishing him. Jacob Mott tried to use this tactic as a roundabout way of undermining the military order he was convicted of disobeying, asking the court to decide that President James Madison’s decision to call up the militia during the War of 1812 was unfounded. The Supreme Court refused to allow this type of lawsuit to be used as a means of escaping the consequences of military dereliction. Contrary to the Trump administration’s claim, however, the decision did not endorse the broader proposition that courts may never, under any circumstances, judge the legality of presidential decisions to call up the National Guard. The Mott opinion focused entirely on preserving the military chain of command, concluding that the President, not lower-level military officials, had the right to make the initial decision about whether the conditions for calling up the militia were met. That question was hotly debated during the War of 1812, after several states claimed that their own military leaders were in charge of deciding whether their militias could be called into federal service. Mott was understood as resolving that dispute. Neither its result nor its reasoning extends to the very different issues raised by California’s case. 

As we next explain, later Supreme Court decisions that cite Mott also do not prohibit courts from reviewing presidential decisions to federalize the National Guard. Nothing in the precedent since Mott has expanded that decision into a wholesale barrier against judicial review whenever statutes give authority to presidents that may be exercised under specified conditions.  

Finally, history demonstrates that judges are capable of evaluating whether the factual conditions necessary for federalizing the National Guard exist. Recognizing as much, the founding-era Congress made prior judicial approval a requirement for presidential action under the original militia statute, and President Washington followed those procedures before employing the militia to combat the Whiskey Rebellion. More recently, the proceedings in this very case demonstrate that courts can evaluate facts and determine whether the legal requirements for employing the Guard are satisfied. There is no barrier to courts reviewing the lawfulness of President Trump’s actions here.