In his massive work, A History of the American People, British historian Paul Johnson observed that American history raises some of the most fundamental questions of meaning and morality. The first question Johnson identified was whether a nation can “rise above the injustices of its origins and, by its moral purpose and performance, atone for them?”

The death of Rosa Parks raises that question anew. Mrs. Parks died Monday at age 92, an icon of the Civil Rights movement and a national symbol of courage and determination. Her iconic stature insured that the news of her death spread around the world. Yet, too many Americans remain unaware of what was at stake when she refused to move to the back of the bus on December 1, 1955.

Racial segregation is a living memory for millions of Americans and an open wound in our national soul, but the vast majority of Americans now living were born after the Montgomery bus boycott and the movement it spawned. To them, Rosa Parks belongs the past, rather than the present. It should not be so.

Mrs. Parks’ death reminds us once again that human sinfulness can take the form of institutionalized hatred and bigotry. Left unchecked and unchallenged, it abuses the oppressed and debases the oppressor. Were we really a nation that forced black persons to ride in the back of the bus, to sit at separate lunch counters, and to drink from racially designated water fountains? Yes, we were.

It is easy now to suggest that time was running out on segregation and that its demise was inevitable. Nothing in human history is inevitable. Individuals like Rosa Parks were instrumental in breaking the back of segregation and revealing its unvarnished evil.

We should note that Rosa Parks had been working up the courage to defy the bus edict for well over a decade. In Rosa Parks, Douglas Brinkley’s biography of Mrs. Parks in the “Penguin Lives” series, Brinkley sets the record straight, documenting her earlier confrontation with segregation on Montgomery’s buses in 1943. He also describes in detail the confusing ugliness of the prevailing policy:

Out of all the Jim Crow laws, those segregating buses were the most complex and arbitrary. With water fountains the apartheid code was simple: One was marked ‘colored,’ the other ‘whites.’ But every bus system in the South seemed to follow a byzantine set of rules, made more confusing by the whims of individual drivers. In Montgomery, for example, all of the city’s buses had thirty-six seats, the first ten always reserved for whites. The ten seats farthest toward the back of the bus were officially designated for the use of African-Americans, provided white passengers didn’t need them. As for the sixteen seats in between, individual drivers imposed their own segregation rules at random and enforced them with the threat of the pistols they carried. This inconsistency of oppression in the Montgomery bus system only added to the unfairness toward black riders, who learned to forgo the middle seats or at least to give them up to any white person if asked.

Paul Johnson’s question remains unanswered — at least in full. Nevertheless, we are indebted to individuals like Rosa Parks, who summoned the courage to confront racial segregation and demonstrate its inherent evil. Her death reminds us of how far America has come — and how far we still must go.