That is the fundamental precept of our legal system. When America fought the War of Independence with Great Britain, people like Patrick Henry were willing to die for their freedom. The American rule of law, and its guarantee of civil rights, assures Americans of free speech and the right to demonstrate. It also prevents civil disasters like Tiananmen Square . When criminals rob people, and it's time for the victim to identify the perpetrator, police use lineups.
Constitutional requirements mandate that lineups are fair.
Sometimes the law must change.