Final answer:
Ryan, as a student-athlete who tested positive for marijuana, is likely not protected under the Fourth Amendment with regard to school-imposed drug testing, which the Supreme Court has found to be legally permissible.
Step-by-step explanation:
In the scenario where 16-year-old Ryan, a high school football team captain, tests positive for marijuana and is subsequently suspended from school and barred from participating in the game, Ryan's protection would largely depend on the school's policies and state law. Generally, public schools have the authority to administer drug tests to student-athletes based on the precedent set by the Supreme Court in cases such as Board of Education v. Earls and Vernonia School District 47J v. Acton that determined such tests do not violate the Fourth Amendment's protection against unreasonable searches and seizures.
The specific Amendment that is commonly referenced in these situations is the Fourth Amendment, which guards against unreasonable searches and seizures by the government. However, the Supreme Court has held that preventing drug use among students is an important enough interest to justify these tests despite the privacy concerns. As such, Ryan is likely not protected under the Fourth Amendment in this context, assuming that his school has a clear policy on drug testing that complies with state and federal law.