Trump's Republican administration alleges the ban violates the Constitution's Second Amendment right to bear arms.
Students of Columbine High School have been asked to participate in a day of service rather than join the National Walk Out on April 20.
Police arrested a 17-year-old female senior at Radnor High School Monday after administrators were alerted that she was writing violent threats.
Authorities said they prevented an "unimaginable tragedy" by foiling John La Due's plot to kill his family and bomb schools.
