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.

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.

The White House says the secretary of state can revoke the visa of Palestinian activist Mahmoud Khalil -- but experts tell ABC News it can't happen without due process.