A federal judge in California is weighing a significant challenge to presidential authority after a trial concluded in a lawsuit contesting the deployment of the California National Guard to the U.

S.

-Mexico border.

The case, which pitted civil liberties advocates against the state and federal governments, centered on whether President Biden overstepped his constitutional powers in ordering the deployment without explicit Congressional authorization.

The trial, spanning several weeks, presented competing arguments about the scope of the president's authority under the Posse Comitatus Act, a law generally restricting the use of the military for domestic law enforcement.

Plaintiffs argued the deployment constituted an unconstitutional use of the National Guard for border security, essentially federalizing a state force without proper legal justification beyond the president's inherent powers as Commander-in-Chief.

They presented evidence suggesting the Guard's role went beyond authorized support functions and encroached upon traditional law enforcement duties.

The defense, representing both the state of California and the federal government, countered that the deployment fell within the president’s executive powers, citing national security concerns and the need to supplement existing border patrol resources.

They emphasized the temporary nature of the deployment and insisted the Guard's activities remained strictly within authorized parameters, focusing on logistical support rather than direct law enforcement.

Judge [Judge's Name], however, appeared deeply skeptical throughout the proceedings, repeatedly questioning the boundaries of the president’s authority in this context.

The judge’s pointed inquiries focused on the lack of clear Congressional approval and the potential for future presidents to use similar deployments to circumvent legislative oversight.

The judge's skepticism was evident in [mention specific example from the trial, e.

g.

, a line of questioning, a ruling, a comment made].

The judge's final ruling, expected in the coming weeks or months, will have significant implications for the balance of power between the executive and legislative branches, and for the future use of the National Guard in domestic deployments.

A decision in favor of the plaintiffs could significantly limit the president's ability to deploy National Guard troops to the border without clear Congressional authorization, potentially requiring future deployments to undergo stricter legal scrutiny.

Conversely, a ruling for the defense would reinforce the executive branch's existing authority in this area, potentially setting a precedent for future actions.

Regardless of the outcome, the case promises to be a landmark legal battle defining the limits of presidential power in a time of increased national security concerns.

The trial over President Trump's deployment of thousands of National Guard troops to Los Angeles earlier this summer reached its , as lawyers for the Justice Department and the state of California argued over the validity of Gov. Gavin Newsom's lawsuit and whether the Posse Comitatus Act — which generally bars the military from engaging in domestic law enforcement – applied to the troop deployment.

4,000 California National Guard troops and 700 Marines to Los Angeles, saying they were needed to protect federal property and law enforcement agents amid June protests against Immigration and Customs Enforcement operations. Newsom did not approve of the use of his state's Guard forces and responded with  requesting an injunction limiting the military's role in the city.

In addition to claiming the 1878 Posse Comitatus Act does not apply, Eric Hamilton, a lawyer for the Department of Justice, argued that there is no precedent for the lawsuit, for injunctive relief or money damages under the act, and that Newsom and the state of California have not suffered the harm required to sue. 

"It is, in fact, the federal government who is engaged in unprecedented conduct," said Deputy Attorney General Meghan Strong, representing the State of California, explaining that the government has never used the military in this way before.                             

U.S. District Judge Charles Breyer seemed perplexed by several of the government's assertions, particularly what he called the apparent "absence of any limits to a national police force." He questioned the Justice Department's claim that the 19th century law at the center of this trial is not relevant, and the assertion that his court lacks jurisdiction to issue an injunction against the president.

"So then what is the remedy?" Breyer asked Hamilton, raising the issue of presidential immunity from criminal prosecution. "You're saying there's a criminal remedy? The president can be prosecuted? You say that in light of the Supreme Court decision, the Trump decision. Isn't he immune?"

"So that's it. Too bad. So sad. It's over," he added emphatically. "And that's the end of the case." 

California has asked Breyer for an injunction that would allow the military to protect federal property — such as courthouses and ICE facilities — but block it from continuing the support for immigration enforcement operations, which the state's lawyer called an "unlawful military crusade."

"The constitution and the law and the facts are on Governor Newsom's side," said Josh Kastenberg, a professor at the University of New Mexico Law School. "But that doesn't mean he's going to win. Ever since World War II, the courts have embraced this military deference doctrine, which really is presidential deference in matters of military command and control."

"We're going to see federal officers everywhere if the president determines that there's some threat to the safety of a federal agent," Breyer said to Hamilton. "And it's his determination. Not mine, it's his. That's what you're saying. That's what the law is."

Hamilton said that wasn't "quite what I'm saying." He asserted the troops are not enforcing federal law, but providing protection, and that it is lawful for guardsmen and marines to provide protection for federal buildings – the one point he agreed with California's attorney on. But, he argued, there is no distinction between protecting federal property and protecting federal law enforcement working out in the field. 

Breyer pointed out that federal employees "are everywhere."

The judge further questioned why any National Guard members remain in Los Angeles, and expressed concern about the justification for continued operations. Hamilton testified that 300 guardsmen remain, a 90% reduction in the force. Strong countered that it is still a significant number of soldiers, and certainly enough to violate the law.

"Thank goodness for the National Guard, but why is the federalized National Guard still in place?" asked Breyer. "What's the threat today? What was the threat yesterday?"

"I go back to the thing that I'm really troubled by: What limiting factors are there to the use of this force?" he said, "Once you have a force in place, and maybe legitimately do so, and the threat that gave rise to the force in that place subsides … how does one look at this national police force that goes out of where the threat was and starts executing other laws?" 

Breyer appeared to take issue with the Justice Department's argument that the Posse Comitatus Act does not apply, noting that a key witness, Major General Scott Sherman – who was at one point the commanding general of the Guard task force in Los Angeles – had testified that the troops were trained to act within the bounds of that law. 

"Then why is it the excellent Major General sought assurance that the Posse Comitatus Act was followed?" said Breyer. "Why did I spend a day looking at slide after slide, and regulation after regulation, and reports after reports on conduct of the soldiers to ensure that they were in compliance with the Posse Comitatus Act if the Posse Comitatus Act is irrelevant?" 

Strong argued that all of the Department of Defense's leaders agreed that the Posse Comitatus Act applied to the Task Force 51 troops in Los Angeles. She said they substituted the word "protection" for "security" when describing the troops' activities because they knew that "security" would violate the act.

She asserted that the secretary of defense had released a memorandum invoking a constitutional exception to the Posse Comitatus Act, and affirmatively instructing soldiers to engage in activities that violated it — but the memo was issued after those activities had taken place. 

On Tuesday, Sherman testified that he was advised of a "constitutional exception" that enabled the troops to conduct certain activities that would normally violate the Posse Comitatus Act.

Strong called this an attempt by the Department of Defense to justify their actions after the fact that "itself reveals a knowledge and awareness of their violations." 

The federal government is "disregarding the law, and so we need show nothing more than that," said Strong. 

She further argued that the Constitution seeks to make sure the president cannot control a standing army the way the king had in 1776. She said that it would deny the basic principles of federalism for the state to have "no legal recourse to challenge the conduct of these troops." 

"If you look at the plain language of the Posse Comitatus Act, and the fear of standing armies that existed at the time of the Constitution," Kastenberg said. "... One of the biggest issues in the state conventions and in the framing of the Constitution to begin with was to significantly curtail the president's authority over the standing army, and keep the standing army very small."  

Breyer did not give a timeline for his ruling, stating at the end of the day, "I will decide the case as soon as I can decide the case."