Edward Kennedy, the senior U.S. senator from the state of Massachusetts, died Tuesday night after a yearlong struggle with cancer. Mr. Kennedy's death deprives the United States of one of its most powerful and eloquent voices, a man who demanded justice and equal opportunities for the country's weakest and most vulnerable citizens. He was an icon whose passing will be sorely missed by all who believe in civil rights and equality and who dream of a more just world.

In many ways, Mr. Kennedy was an unlikely hero. He was the youngest of four brothers from one of America's most powerful political dynasties. While the Kennedys have been a driving force for liberalism in U.S. politics, their wealth and privilege could easily have pushed them toward conservative positions. Instead, they came to embody the very essence of noblesse oblige.

It was assumed that the four siblings would enter public service, but Mr. Kennedy was always overshadowed by his older brothers. Tragically, all of them were struck down in their prime. Joseph Kennedy Jr., the eldest brother, was killed in a plane crash in World War II. John and Robert would be felled by assassins' bullets. Only "Teddy," the youngest, would die a natural death at age 77.