The First Amendment does not protect against schools prohibiting students from displaying messages promoting illegaldrug use at a school sponsored event.
because
score: 3
Freedom of Speech in schools is not as extensive as it is when applied to adults outside of a school setting.
According to Tinker V. Des Moines Independent School District, as long as the speech does not cause a disturbance it is within the rights of the First Amendment.
Though students may have a right to free political speech in schools, it does not extend to messages promoting drug use since it undermines the school's campaign to discourage drug use.