Mahmoud Khalil, a pro-Palestine advocate detained by US Immigration and Customs Enforcement (ICE) in March 2025, will take his case to the US Supreme Court after a federal appeals court declined by a 6-5 vote to rehear his legal challenge. Khalil, a permanent US resident who has never been charged with a crime, argues that the Trump administration is targeting him for constitutionally protected speech under a rarely invoked immigration provision that allows deportation of those deemed a national security threat based on lawful beliefs or associations. The case is widely seen as a test of whether the government can use immigration enforcement to suppress political expression, with civil liberties groups warning that a ruling against Khalil would set a precedent enabling authorities to deport anyone for opinions the administration opposes.