PHILADELPHIA—The Knight First Amendment Institute at Columbia University today filed an amicus brief in Khalil v. Trump, urging the U.S. Court of Appeals for the Third Circuit to find that the government’s detention and attempted deportation of Mahmoud Khalil on the basis of his protected speech is unconstitutional. The brief draws on the testimony of government officials during the recent trial in AAUP v. Rubio, a case brought by the Knight Institute challenging the Trump administration’s policy of arresting, detaining, and deporting noncitizen faculty and students for their pro-Palestinian advocacy. 

 “The Trump administration targeted Mahmoud Khalil as part of its broader effort to punish student protesters for engaging in lawful political speech,” said Xiangnong (George) Wang, staff attorney at the Knight Institute. “Senior officials have admitted that, in carrying out this policy, they relied on unvetted allegations from unreliable third-party websites and routinely conflated pro-Palestinian advocacy with antisemitism and support for terrorism. All of this confirms that the Trump administration's basis for detaining and attempting to deport Mr. Khalil was unconstitutional.”

Highlighting the testimony of government officials during a recent trial in AAUP v. Rubio, today’s brief shows that the Trump administration targeted Mr. Khalil as part of its ideological deportation policy, under which officials sought to deport student protesters based on unvetted third-party allegations that the students had engaged in speech that was antisemitic or pro-Hamas,. The brief argues that the policy and its implementation raise serious concerns under the Fifth Amendment’s void-for-vagueness doctrine, which requires the government to provide the public fair warning of what otherwise lawful political advocacy could result in detention or deportation and to supply explicit standards to guide those tasked with enforcing a policy. 

Read today’s brief here.

Read more about the case here.

On March 25, 2025, the Knight Institute filed a lawsuit on behalf of the American Association of University Professors and the Middle East Studies Association, challenging the Trump administration’s ideological deportation policy. During a two-week trial that took place in July before Judge William G. Young of the U.S. District Court for the District of Massachusetts, witness testimony uncovered a wealth of details about the policy and its effects on campuses across the country. A ruling is expected in the case later this month. Read more about AAUP v. Rubio here. Read a summary of the trial testimony here.

For more information, contact: Adriana Lamirande, [email protected]