Troops in California: Legal and Constitutional Implications of Federalization

June 23, 2025 By Kelli Rosellini

California v. Trump may become a defining federalism case of the 21st century; a test of the limits of presidential power, state sovereignty, and judicial oversight. The deployment of federal troops against the will of a state governor revives historical concerns about executive overreach, militarization, and erosion of civilian control over domestic affairs. This is not the first time a sitting President has federalized troops.

The California case could soon reach the Supreme Court, especially if Judge Breyer’s pending ruling on the US Marine deployment finds a Posse Comitatus Act violation. Such a decision would demand clarification of the permissible scope of military activity during federal emergencies. A question with few precedents and high constitutional significance.

However this ends up, all of our rights are affected.

California v. Trump (9th Circuit Court of Appeals, 2025)

In June 2025, the U.S. Court of Appeals for the Ninth Circuit issued a ruling temporarily upholding President Donald J. Trump’s federalization of the California National Guard and deployment of U.S. Marines in response to extended civil unrest in Los Angeles. The unrest followed a series of federal immigration raids that sparked mass protests, violence, and significant disruption of public order.

The Ninth Circuit panel (comprised of two Trump-appointed judges and one Biden appointee) stayed a ruling (meaning, put on hold) by U.S. District Judge Charles Breyer, which had found that Trump’s actions violated the requirements of 10 U.S.C. §§ 251–255, commonly referred to as the Insurrection Act. Judge Breyer ruled that the prerequisites for federalizing the National Guard, including a “rebellion” or the failure of regular law enforcement to execute federal law, were not satisfied, and that Trump failed to coordinate with Governor Gavin Newsom as statutorily required.

In a sharply divided political and legal climate, this case now centers on several enduring constitutional doctrines: the scope of executive power, the sovereignty of states, and the judicial reviewability of presidential national security judgments. This is not a singular issue, rather it is layered with multiple authorities and restrictions for the President.

Presidential Authority Under the Insurrection Act

The Insurrection Act was originally passed in 1792 as part of the early Republic’s effort to empower the federal government to suppress domestic uprisings and enforce federal law when states could not or would not do so. The law was enacted in response to events like the Whiskey Rebellion (1791 to 1794), in which frontier farmers violently resisted a federal excise tax on distilled spirits. President George Washington invoked the 1792 law to federalize state militias and personally led troops into western Pennsylvania to restore order.

Codified and amended over time, most notably in 1807, 1861, and 1871, the Insurrection Act authorizes the President to deploy U.S. armed forces domestically under three broad scenarios:

1. 10 U.S.C. § 251: At the request of a state governor to suppress insurrection.
2. 10 U.S.C. § 252: When obstruction to the execution of federal law makes it “impracticable” to enforce those laws by ordinary means.
3. 10 U.S.C. § 253: To suppress “insurrection, domestic violence, unlawful combination, or conspiracy” that deprives people of constitutional rights, even without a state’s request.

In California v. Trump, the administration argued that § 252 was satisfied due to what it called a “breakdown in civil order”: Molotov cocktails, dumpster ramming, and violent assaults on immigration officials. An example of the state not handling a domestic uprising. The Ninth Circuit agreed in principle, stating that the “execution of federal law [had] been frustrated,” which likely met the statutory threshold.

This interpretation mirrors broad executive discretion seen in past precedents. For example, in United States v. Wounded Knee Legal Defense/Offense Committee, 507 F.2d 1043 (8th Cir. 1974), the court upheld deployment under the Insurrection Act without detailed judicial second-guessing of the President’s factual determination.

However, scholars have argued that such deference risks allowing the Act to become a tool for political repression. This is not the first time Donald Trump has considered invoking the Insurrection Act. During the nationwide protests following the killing of George Floyd in May–June 2020, President Trump publicly threatened to use the Insurrection Act to deploy active-duty military forces domestically, without the request of state governors.

See:

• Stephen Vladeck, “The Calling Forth Clause and the Domestic Deployment of the Military,” Yale Law Journal Forum (2019), available at: https://www.yalelawjournal.org/forum

10th Amendment and State Sovereignty

At the core of California’s challenge is the 10th Amendment, which reserves to the states all powers not delegated to the federal government. The National Guard, although funded federally, is traditionally under the control of the state governor unless federalized under Title 10 of the U.S. Code.

Judge Breyer’s ruling relied in part on the 10th Amendment and cases like Printz v. United States, 521 U.S. 898 (1997), which emphasized that the federal government cannot compel states or state officers to carry out federal mandates.

Governor Newsom argued that federalizing the Guard over state objection violated California’s sovereign prerogative to maintain civil order. While the Ninth Circuit disagreed, it left open the door for further review of how the Guard was used after federalization.

As the court wrote:

“Nothing in our decision addresses the nature of the activities in which the federalized National Guard may engage.”

This echoes concerns raised in scholarship such as:

• Rachel E. VanLandingham, “Soldiers, the Posse Comitatus Act, and the Use of Force on American Soil,” SMU Law Review, Vol. 71, 2018.

Posse Comitatus Act & the Marines

Perhaps the most constitutionally precarious action is the deployment of 700 U.S. Marines into Los Angeles — a clear test of the Posse Comitatus Act (PCA), 18 U.S.C. § 1385. The PCA prohibits the use of federal troops in civilian law enforcement unless explicitly authorized by Congress or the Constitution.

The U.S. Marine Corps, unlike the National Guard under state control, is subject to PCA restrictions. Historically, violations occur when federal troops:

• Conduct arrests or searches,
• Seize property,
• Perform investigative roles traditionally done by police.

In United States v. Red Feather, 392 F. Supp. 916 (D.S.D. 1975), the court found that indirect support (e.g., equipment, advice) by the military did not violate the PCA, but direct law enforcement action would.

In the current case, Trump’s administration has insisted that the Marines are not engaging in law enforcement, but are only protecting federal buildings and ICE personnel. However, California’s complaint argues that Marines have already engaged in street-level operations and citizen arrests potentially violating both PCA and DoD Directive 3025.18 (Defense Support of Civil Authorities).

Judge Breyer has not yet ruled on the legality of this deployment, but a ruling against it would create a rare judicial precedent enforcing the PCA in a modern setting.

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Judicial Reviewability of Presidential Emergency Powers

One of the most significant constitutional questions raised is whether courts can review the President’s determination that a domestic emergency exists justifying troop deployment.

The Department of Justice argued that once the President invokes the Insurrection Act, courts may not second-guess that decision — an echo of the “political question doctrine.” The Ninth Circuit rejected that claim, asserting:

“We reject the idea that no court or state governor can review the President’s judgment.” 9th Circuit Court

This aligns with foundational cases like:

• Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579 (1952): Presidential emergency powers are not unlimited, especially when not authorized by Congress.
• Hamdi v. Rumsfeld, 542 U.S. 507 (2004): The Court affirmed the judiciary’s role in reviewing executive wartime actions.

Such rulings reinforce the proposition that executive discretion is not immune from judicial scrutiny, particularly when civil liberties are at stake.

References

1. California v. Trump, No. ___ (9th Cir. June 2025) — reported summary. No published opinion yet on Cornell or academic repositories due to recency.
2. United States v. Red Feather, 392 F. Supp. 916 (D.S.D. 1975).
3. Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579 (1952).
4. Hamdi v. Rumsfeld, 542 U.S. 507 (2004).
5. Printz v. United States, 521 U.S. 898 (1997).
6. Vladeck, Stephen I., “The Calling Forth Clause and the Domestic Deployment of the Military,” Yale Law Journal Forum, 2019.
7. VanLandingham, Rachel E., “Soldiers, the Posse Comitatus Act, and the Use of Force on American Soil,” SMU Law Review, Vol. 71, 2018.
8. 10 U.S.C. §§ 251–255 (Insurrection Act).
9. 18 U.S.C. § 1385 (Posse Comitatus Act).
10. DoD Directive 3025.18, Defense Support of Civil Authorities (DSCA), 2018 revision.