Every step of the criminal process – ascertaining whether a criminal offense was committed, detecting and arresting suspects, interrogation of suspects, searches and seizures to obtain evidence, police lineups and other identification procedures, and admission of evidence at trial – involves potential conflicts between the mission of law enforcement officers to find criminals and bring them to justice, and the rights of individuals in our democratic society to remain free of unwarranted government intrusion. These conflicts are ultimately resolved by courts, which are called upon in a wide variety of factual circumstances to weigh law enforcement imperatives against the protection of individual rights.