The Fourth Amendment to the United States Constitution states that people have a right to be secure against unreasonable searches of themselves and their belongings.

The United States Supreme Court has decided that the Fourth Amendment applies to schools and that a search must meet the following requirements:

1. The motivation for the search must be reasonable in light of the information that the school official obtained that made him or her think a search was necessary; and

2. The measures adopted for the search must be reasonably related to the objectives of the search and not excessively intrusive in light of the age and sex of the student and the nature of the infraction.

A 'reasonable suspicion' is a belief or opinion based on the facts or circumstances. So if a school official has a reasonable suspicion that some wrong doing has occurred and that evidence of that may be found in your backpack, that official can probably search your backpack without your permission