Penn CERL argues Trump violated constitutional principles by deploying National Guard to Chicago

The Center for Ethics and the Rule of Law filed an amicus brief with the Supreme Court on behalf of more than 150 members of Congress opposing 1968 Wharton graduate and President Donald Trump’s deployment of the National Guard to Chicago on Monday.

The Nov. 10 brief — filed in Donald J. Trump v. State of Illinois — was principally authored by Penn Carey Law professor and CERL Faculty Director Claire Finkelstein and filed by CERL Distinguished Senior Fellow Brenner Fissell. The brief centers on the interpretation of a federal code which allows the President to call forth the National Guard under three specific circumstances: to forestall a foreign invasion, when there is a rebellion or danger of rebellion against the United States, or when the President cannot execute federal laws with regular forces. 

The filing argues that Trump's invocation of this statute — to justify the use of the Illinois and Texas National Guard — exceeded his authority and threatened core constitutional principles. 

"Congress partially delegated that authority to the President under certain specific circumstances. When a case or controversy arises over the meaning of such a statute, it falls to the judiciary to interpret it," the Nov. 10 brief read.

According to a press release from Sen. Dick Durbin's (D-Ill.) office, the congressional amici named in the brief include Senate Majority Leader Chuck Schumer (D-N.Y.), House Minority Leader Hakeem Jeffries (D-N.Y.), and Sen. Tammy Duckworth (D-Ill.).

CERL’s filing challenged Trump’s assertion that courts must fully defer to presidential decisions regarding National Guard deployment. The brief argued that total deference to the executive branch would risk infringing upon Americans' First and Fourth Amendment rights.

“Whatever deference may be appropriate when the President is acting in his Commander-in-Chief capacity in a theatre of war, no such basis for deference obtains when the President is exercising congressionally delegated authority domestically, in a peacetime military deployment, unless the legislature has chosen to provide otherwise,” the brief added.

The Monday filing marked CERL's second major intervention in legal challenges to Trump's National Guard deployments. In August, the center filed an amicus brief in Newsom v. Trump, challenging the President's attempt to federalize the California National Guard against the wishes of California Gov. Gavin Newsom. 

That brief, primarily authored by Penn Carey Law professor and CERL Faculty Director Claire Finkelstein, warned that Trump's executive action undermined federalism, violated the Posse Comitatus Act's prohibition on military involvement in law enforcement, and threatened constitutional rights.

The Illinois case raises similar concerns to those Finkelstein previously expressed about the California deployment.

Trump's deployment to Chicago follows his use of the D.C. National Guard for what he stated were purposes of addressing homelessness, beautifying the city, and controlling crime — despite crime in the district dropping roughly 27% since 2024, as Finkelstein noted in a previous interview with The Daily Pennsylvanian.

Unlike in Washington, D.C., where a Home Rule statute gives the President direct authority over the Guard, deployments to states like Illinois test legal boundaries between presidential authority and state sovereignty.

The Supreme Court brief emphasized that excessive deference to the President in this context would undercut Congress' constitutionally-granted ability to create policy.

“To defer entirely to the interpretation of the executive branch as to the authority Congress has granted under the statute and the meaning of its provisions would be tantamount to stripping Congress of its authority to legislate under the Militia Clauses,” the brief reads.

The filing also addressed Trump's deployment targeting individuals expressing opposition to government policies, noting the deployment of National Guard troops in Chicago, Portland, and Los Angeles target individuals exercising their First Amendment rights.

“[W]hen the constitutional rights of Americans are under threat by presidential decision-making regarding use of the military, deference to presidential authority is not warranted, and federal courts have a mandate, indeed a duty, to intervene,” the brief stated.

The amicus brief further argued that Trump's argument would effectively eliminate the Supreme Court's role in “reviewing congressional delegations of authority entirely.”

“The President is claiming that once Congress has delegated this authority to him, even federal courts cannot review the interpretation of the law he chooses, or the factual claims that underly it,” the brief read. “That position is inconsistent with the Constitution, with Congress's intentions, and with the express language in 10 U.S.C. § 12406.”

Correction: A previous version of this article stated that the amicus brief was authored by CERL Distinguished Senior Fellow Brenner Fissell. The article has been updated to reflect that the brief was authored by Penn Carey Law Professor and CERL Faculty Director Claire Finkelstein and filed by Fissell. The DP regrets the error.

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