A federal appeals court on Friday denied Columbia University pro-Palestinian activist Mahmoud Khalil’s request for a full-court rehearing, leaving in place a ruling that blocks him from challenging his detention in federal district court while his immigration case proceeds.

The decision means Khalil must pursue his constitutional claims — including allegations that he was targeted over pro-Palestinian advocacy and unlawfully detained — through the immigration appeals process after a final removal order. 

Khalil, a green card holder who is married to an American citizen, was released from ICE custody last June following his arrest by federal agents in New York City in March 2025.

He was detained on the basis of Secretary of State Marco Rubio’s determination that his speech would “compromise a compelling U.S. foreign policy interest.”

Three judges dissented from the denial of rehearing, writing on Friday that the ruling “imperils the civil liberties of Petitioner Mahmoud Khalil and similarly situated noncitizens” and that “the consequences are profound.” 

“We cannot fulfill that role if we write ourselves out of relevance and leave the Executive Branch to check itself,” the judges wrote.

Last month, Khalil was issued a final order of removal from the Board of Immigration Appeals in a separate case, but his attorneys say other court orders bar the Trump administration from detaining him for the moment.

In response to the appeals court ruling denying a rehearing of Khalil’s detention case, the American Civil Liberties Union said it will seek Supreme Court review of Friday’s decision.

“We hope the Supreme Court will recognize how dangerous the Third Circuit’s decision was, not just for Mahmoud but for other non-citizens the administration has set its vengeful sights upon,” said Baher Azmy, legal director of the Center for Constitutional Rights in a statement.

“That ruling greenlights holding someone in prolonged, brutal detention conditions without access to meaningful judicial review in order to punish them and deter others from dissenting from U.S. foreign policy,” Azmy added. “We are honored to continue to stand with Mahmoud as he keeps fighting for Palestinian rights, the rights of immigrants brutalized by DHS policies, and the right of people to speak out against injustice.”