When Mahmoud Khalil, who helped lead pro-Palestinian demonstrations while a Columbia University student, was detained this month, the Trump administration argued he should be deported to help prevent the spread of antisemitism, invoking a rarely used law.
Lawyers for Mr. Khalil, a legal permanent resident who is being detained in Louisiana, quickly responded that the administration was retaliating against their client for his constitutionally protected speech criticizing Israel and promoting Palestinian rights.
Last week, the government quietly added new accusations to its case against Mr. Khalil, saying that he had willfully failed to disclose his membership in several organizations, including a United Nations agency that helps Palestinian refugees, when he applied to become a permanent U.S. resident last March. It said he also failed to disclose work he did for the British government after 2022.
The Trump administration appears to be using the new allegations in part to sidestep the First Amendment issues raised by Mr. Khalil’s case. On Sunday, in a filing opposing his release, Justice Department lawyers argued that the new allegations reduced the importance of concerns about Mr. Khalil’s right to free speech.
“Khalil’s First Amendment allegations are a red herring,” they wrote. Given the new allegations, they added, there was an “independent basis” for his deportation.
Lawyers for Mr. Khalil, who are fighting for his release in a New Jersey federal court, did not immediately respond to requests for comment. They are expected to argue that the new accusations are pretext for continued retaliation against their client’s speech and his continued detention far from his home and family. Mr. Khalil’s wife, an American citizen who lives in New York City, is expected to give birth next month.
The new allegations, listed in a document from the Homeland Security Department, include that Mr. Khalil did not disclose his work with the U.N. agency or Columbia University Apartheid Divest, a coalition of student groups that set off pro-Palestinian demonstrations at the school. Mr. Khalil earned a master’s degree from Columbia in December.
The government also said that Mr. Khalil failed to list his continuing employment with the Syria Office in the British Embassy in Beirut, Lebanon, after 2022.
The efforts of Mr. Khalil’s lawyers in New Jersey to secure his release are separate from the immigration court proceedings — currently being held in Louisiana — that could lead to his deportation. But in order to deport Mr. Khalil on the basis of the new allegations, the government would have to convince an immigration judge that any failure to disclose the relevant information was willful, and that it would have made a difference in his chances of receiving legal permanent residency status.
The Trump administration is also standing by its original justification for Mr. Khalil’s detention, citing a little-used law that says the secretary of state can initiate deportation proceedings against noncitizens whose presence in the United States can reasonably be considered a threat to the country’s foreign-policy agenda.
The secretary of state, Marco Rubio, has accused Mr. Khalil of participating in antisemitic activities, referring to protests on Columbia’s campus at which, the secretary said, students expressed support for Hamas.
Mr. Khalil’s lawyers have denied that their client promoted Hamas and have argued more generally that their client’s speech is protected by the First Amendment. They are expected to challenge the constitutionality of the law Mr. Rubio used to initially justify Mr. Khalil’s detention.
Jesse Furman, a federal judge in New York who reviewed Mr. Khalil’s case before transferring it to New Jersey last week, said that the First and Fifth Amendment issues raised by the case warranted careful review.
“The fundamental constitutional principle that all persons in the United States are entitled to due process of law demands no less,” he wrote.
