The Trump administration’s effort to have his case heard in Louisiana could let some of America’s most conservative judges set a precedent on deportations.

The Trump administration’s detention of a green-card holder who was a leader in the Columbia University protests against Israel has put a face on the debate over immigration and the limits of free speech, with a sympathetic twist: The man, Mahmoud Khalil, is married to an American, and they are expecting their first child next month.