The Fourth Amendment provides another important protection from police. This Amendment protects citizens against unreasonable searches and seizures. As the Supreme Court concluded, this protection extends to searches and seizures of property and searches and seizures of the person, in the form of police stop-and-frisks and arrests. It means that police must meet certain requirements before they can stop and interrogate an individual, and even more stringent requirements before they can place that individual under arrest.
In order to conduct a Terry stop (named after the 1968 Supreme Court case that established this test), police officers can stop and briefly detain a person only if, based upon the officers’ training and experience, there is reason to believe that the individual is engaging in criminal activity. This test is known as the reasonable suspicion standard. Unless this standard has been met, the Fourth Amendment protects citizens from being stopped by the police.
In order to arrest an individual, police must satisfy the probable cause standard. According to the Supreme Court, probable cause to make an arrest exists when an officer has knowledge of such facts as would lead a reasonable person to believe that a particular individual is committing, has committed, or is about to commit a criminal act. Additionally, the arresting officer must be able to articulate the specific facts and circumstances forming the basis for probable cause. Unless the officer is able to do this, the Fourth Amendment prevents him or her from arresting the individual.
Considering the Fourth Amendment along with the Fifth Amendment, as discussed in the October 30, 2015, post, it is clear that the Constitution has created certain situations in which citizens are not compelled to cooperate with police.