A New York federal judge is set to hear pivotal questions in the case of Mahmoud Khalil, a leader of large Gaza solidarity protests at Columbia University who now faces deportation after his arrest by Immigration and Customs Enforcement agents.

Experts say there has to be a legal basis to revoke a person’s residency status, and removal needs to be ordered by an immigration judge.

The current administration wants to go after protesters using an obscure Cold War-era statute.

Mr. Khalil, who helped lead protests at Columbia University against civilian casualties in Gaza, was arrested by immigration officers and sent to a detention center in Louisiana.