Washington — President Trump warned Monday that this weekend's arrest of prominent Palestinian activist Mahmoud Khalil by federal immigration authorities is the first "of many to come" amid his administration's crackdown on students and alleged "agitators" protesting Israel's war with Hamas in Gaza. The same day, a federal judge blocked Khalil's deportation and scheduled a court hearing after Khalil's attorney filed a petition challenging the arrest. The president wrote in a post on his social media platform Truth Social that his administration "will not tolerate" what he said is "pro-terrorist, anti-Semitic, anti-American" activity on college campuses across the country, and...