ANSWER -
Case #1: The search and seizure of the men was not in violation of the Fourth Amendment. The officer had reasonable suspicion based on his observation of the men casing a job, which justified the stop and search. The Fourth Amendment allows for reasonable searches and seizures, and in this case, the officer had sufficient grounds to believe the men were engaged in criminal activity.
Case #3: Random drug testing of public school students by school officials does violate the 4th Amendment. The Supreme Court has ruled that in order for a search to be reasonable, it must be based on individualized suspicion of wrongdoing. In this case, the school district's policy of random drug testing did not meet that standard, and therefore violated the students' Fourth Amendment rights.
Case #4: The police should be able to wiretap public phones, but only with a warrant based on probable cause. The Fourth Amendment protects individuals from unreasonable searches and seizures, and the Supreme Court has held that wiretapping constitutes a search under the Fourth Amendment. Therefore, a warrant based on probable cause is required in order to wiretap a public phone. In this case, it is unclear whether the police obtained a warrant, but if they did, the wiretapping would be constitutional. If they did not, it would be a violation of the Fourth Amendment.