Supreme Court to Review Trump's Federalization of National Guard in Chicago, Nationwide Implications

On October 29, 2025, the U.S. Supreme Court took the rare step of requesting additional briefing in a high-profile emergency case challenging President Trump’s federalization of the National Guard in Chicago for immigration enforcement, signaling the Court is grappling with fundamental questions about presidential authority over state military forces. The Court’s decision will have nationwide implications for National Guard deployments, with similar litigation pending in California, Oregon, and other states.

Background of the Chicago Deployment:

Trump federalized 300 members of the Illinois National Guard earlier in October 2025 to “protect officers and federal property” outside Chicago, arguing this was necessary to confront protesters at an ICE facility who he claimed were engaged in “coordinated, violent opposition to the enforcement of federal law.” Another 400 federalized members of the Texas National Guard were also deployed to Illinois.

Lower Court Rulings - Both Blocked Trump:

U.S. District Judge April Perry issued a temporary restraining order on October 9 prohibiting Trump “from ordering the federalization and deployment of the National Guard of the United States within Illinois” for two weeks, later extending the order. Judge Perry found the administration hadn’t attempted using regular federal forces first, as required by statute.

U.S. Court of Appeals for the 7th Circuit upheld Judge Perry’s order barring the National Guard deployment, agreeing Trump had not met the statutory requirements for federalizing state military forces.

Supreme Court’s Critical Question:

Rather than quickly ruling for or against Trump, the Supreme Court ordered both parties to file supplemental briefs by November 10 addressing a fundamental statutory interpretation question:

“Does the term ‘regular forces’ refer to the regular forces of the United States military, and if so, how does that interpretation affect the operation” of the federal law Trump invoked to federalize the Guard?

This question goes to the heart of when a president can federalize state National Guard units. The statute allows federalization when the president cannot “with the regular forces … execute the laws of the United States.” The Court is asking whether “regular forces” means:

• Narrow interpretation: Only the active-duty U.S. military (Army, Navy, Air Force, Marines)
• Broad interpretation: All federal law enforcement agencies (ICE, CBP, FBI, ATF, DEA, etc.)

If “regular forces” means only military, Trump could more easily federalize the Guard for any law enforcement purpose. If it includes all federal law enforcement, Trump would have to exhaust ICE, CBP, FBI, and other agencies before federalizing state troops.

Significance of Requesting Additional Briefing:

The Court’s request for supplemental briefs is highly unusual in emergency cases and signals:

• The Court is not rushing to rule - Reply briefs due Nov 17, suggesting no decision until after Thanksgiving
• The justices are divided on fundamental questions about presidential power
• This case has major implications beyond Chicago - the Court recognizes this will set precedent for all future National Guard federalizations
• The conservative majority may be hesitating - if they were confident in Trump’s authority, they would have quickly overturned the lower courts

Nationwide Litigation:

The Supreme Court’s decision will affect pending cases in:

• California: Lawsuit over Trump’s June 2025 federalization of California National Guard over Governor Newsom’s objection
• Oregon: Similar challenge to National Guard federalization
• Multiple other states: Where Trump has threatened to federalize Guard units for immigration enforcement

Constitutional Questions at Stake:

1. Separation of Powers: Can the president use military forces for domestic law enforcement when civilian agencies are available?
2. Federalism: Can the president override governors and commandeer state military forces against state wishes?
3. Posse Comitatus: Does using the National Guard for immigration enforcement violate the principle against military involvement in civilian law enforcement?
4. Statutory Authority: What does “cannot with the regular forces execute the laws” actually mean?

Implications of Potential Rulings:

If SCOTUS Rules for Trump:

• Presidents can federalize state National Guard for any law enforcement purpose
• Governors lose control over their own military forces
• Opens door to using military for domestic political purposes
• Enables Trump to deploy Guard nationwide for immigration crackdowns
• Effectively militarizes domestic law enforcement

If SCOTUS Rules Against Trump:

• Presidents must exhaust civilian law enforcement before using military
• Governors retain authority over state Guard units
• Maintains separation between military and civilian law enforcement
• Limits Trump’s ability to use military for immigration
• Upholds federalism and state sovereignty

Political Context:

The case poses “one of the most consequential tests for the justices in President Donald Trump’s second term.” The Court’s conservative supermajority faces a tension between:

• Deference to presidential authority (which conservatives typically favor)
• Federalism and state rights (which conservatives also traditionally support)
• Limiting military involvement in civilian affairs (a principle conservatives have historically defended)

The Court’s request for additional time and briefing suggests the conservative justices may be divided on how to resolve these competing principles when Trump is asking to override Democratic governors and use military forces against civilian protesters.