Detained activist Mahmoud Khalil, arrested at Columbia University, urges continued student pro-Palestinian protests in a letter from a Louisiana detention center. Khalil's arrest is part of a crackdown on campus anti-Israel protests, with the Trump administration accusing the movement of supporting terrorism and contributing to a rise in antisemitism. He calls for unity in defending the right to protest for Palestine and highlights the importance of civil liberties. Khalil also blames Columbia's leaders for his arrest, accusing them of enabling the US government to target him.