Can you sue a school for being attacked by a hostile student whom they knew was hostile yet chose to keep in school?

Yes, it is possible to sue a school if a student is attacked by a hostile peer whom the school knew posed a threat and chose to keep in the school. This could be considered a failure to provide a safe environment, potentially violating the duty of care owed to students. However, the success of such a lawsuit would depend on the specific circumstances, evidence of the school's knowledge of the threat, and the legal standards in the jurisdiction. Legal advice should be sought to evaluate the viability of the case.