President Donald Trump, California Gov. Gavin Newsom. (Getty Images)
Breyer, who is the brother of retired liberal Supreme Court Justice Stephen Breyer, did not make any decisions from the bench during the hearing and did not signal how he would rule. He indicated that a decision would come as soon as Thursday evening.
The judge's remarks came as he weighed arguments presented by DOJ Civil Division head Brett Shumate. Shumate argued the courts do not even have authority to review Trump's invocation of Title 10, a set of laws that lays out what mechanisms a president can use to federalize National Guard members.
The National Guard is a state-based military force under the dual control of presidents and governors. Typically, a president activates the National Guard with a governor's consent.
But, as demonstrated in the courtroom in Northern California on Thursday, the law does not make clear that a governor's permission is necessary.
The Title 10 law that Trump and Secretary of Defense Pete Hegseth relied on to federalize thousands of National Guard members says presidents must go "through" a governor. A memorandum Hegseth sent out deploying the soldiers states that he went through Newsom, a point Breyer questioned.
A rioter waves a Mexican national flag next to a car on fire during a protest following federal immigration operations, in the Compton neighborhood of Los Angeles, California on June 7, 2025. (Getty Images)
California's attorney general filed a lawsuit over Trump's actions, pitting the president against Newsom, one of the most prominent Democrats in the country and a possible 2028 presidential contender.
Attorneys for Newsom argued in a complaint that Trump and Hegseth exceeded their authority, violated Title 10, and violated the Administrative Procedure Act.
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They "unlawfully bypassed the Governor of California," the attorneys wrote. In addition to possibly requiring consent from a governor, Title 10 also requires that there be a rebellion or similar type of scenario that is underway.
"At no point in the past three days has there been a rebellion or an insurrection," the attorneys wrote. "Nor have these protests risen to the level of protests or riots that Los Angeles and other major cities have seen at points in the past, including in recent years."
Ashley Oliver is a reporter for Fox News Digital and FOX Business, covering the Justice Department and legal affairs. Email story tips to ashley.oliver@fox.com.
https://www.foxnews.com/politics/judge-mulls-trumps-authority-over-national-guard-warns-us-not-king-george-monarchy