Final answer:
The civil rights campaign in Birmingham in 1963 is an example from American history that illustrates Dr. King's point that "justice too long delayed is justice denied." Peaceful protests were met with violence, and Dr. King argued that African Americans had waited patiently for too long.
Step-by-step explanation:
One example from American history that illustrates Dr. King's point that "justice too long delayed is justice denied" is the civil rights campaign in Birmingham in 1963. In this campaign, peaceful protests were met with violence from the police who attacked demonstrators, including children, with fire hoses and dogs. The world witnessed these acts of injustice and thousands were arrested. Dr. King, who was jailed during this campaign, responded with his powerful "Letter from a Birmingham Jail," where he argued that African Americans had waited patiently for over 300 years for their rights and that the time for waiting was over.