...not embrace merely the classroom hours. When he is in the cafeteria, or on the playing field, or on the campus during the authorized hours, he may express his opinions, even on controversial subject like the conflict in Vietnam, if he does so without 'materially and substantially interfering]...

...showing that petitioners' exercise of their speech rights would "materially and substantially interfere with the requirements of appropriate discipline in the operation of the school. . . ." Id. at 509. This suggests that it is only where undesirable disruption occurs that activity...

...showing that petitioners' exercise of their speech rights would "materially and substantially interfere with the requirements of appropriate discipline in the operation of the school. . . ." Id. at 509. This suggests that it is only where undesirable disruption occurs that activity...

...showing that petitioners' exercise of their speech rights would "materially and substantially interfere with the requirements of appropriate discipline in the operation of the school. . . ." Id. at 509. This suggests that it is only where undesirable disruption occurs that activity...

...finding or showing that engaging in the forbidden conduct would materially and substantially interfere with the requirements of appropriate discipline in the operation of the school, the prohibition cannot be sustained. 6. The school authorities in Des Moines did not purport to prohibit...

...and no showing that engaging in the forbidden conduct would materially and substantially interfere with the requirements of appropriate discipline in the operation of the school, the prohibition cannot be sustained.28 In delivering the majority opinion of the Court, Mr. Justice...

...showing that exercises of fundamental constitutional rights would "materially and substantially interfere with the requirements of appropriate discipline in the operation of the school" , the prohibition of the exercise of those rights cannot be countenanced. "In our system, students...

...right to express their opinions on controversial subjects on the school grounds so long as they do so without " "materially and substantially interfer[ing]...and without colliding with the rights of others." Id. at 513. "In our system, students may not be regarded as closed-circuit recipients of only that...

...guaranteed on the public high school campus if it does not (1) materially and substantially interfere with the requirements of appropriate discipline in the operation of the school) and, (2) does not invade or collide with the rights of others. Id. at 513. Obviously, allowing a student...

...showing that engaging in any of the forbidden conduct would 'materially and substantially interfere with the requirements of appropriate discipline in the operation of the school,' the prohibition cannot be sustained."27 If one combines these points with the thrust of the clear and...