For the young, the America of 40 years ago must be difficult to imagine. For those who were there, it can be painful to remember.

The assassination of the Rev. Martin Luther King Jr., 40 years ago today in Memphis, was another in a seemingly endless line of disturbing events that were challenging the very notion of the great American experiment. The Vietnam War was tearing apart college campuses nationwide. A hedonistic movement among the nation's young adults threatened time-honored notions of morality and family. King's assassination was to be closely followed by the murder of Sen. Robert F. Kennedy just as he seemed ready to win the Democratic nomination for president, and then by the Democratic convention itself, which prompted riots in the streets of Chicago. Racial tensions threatened hundreds of cities.

If a time machine were available, folks in 1968 would be astounded by a journey to our time, and no doubt relieved by how orderly society is by comparison. They would marvel that a black man today is leading the charge toward the Democratic nomination, that the nation has a black woman as secretary of state and that other black people of both genders occupy important and prominent positions.

But we're not sure King would share the feeling that all is well. At the time of his death, he was beginning to turn his attention to the plight of the nation's poor, who lived with little hope and few opportunities. On that front, despite the great successes of many blacks, little has changed.

The Washington Post recently put this in perspective. It asked readers to imagine three black kindergarten boys, all equally intelligent and promising. According to statistics and studies, in a little more than 10 years one of them will be in prison, one will be thinking of dropping out of high school to face a life with few chances, and one will be zooming toward a successful life.

Chief among the obstacles they face will be a fractured family life. Comedian Bill Cosby and Harvard professor Dr. Alvin Poussaint recently collaborated on a book, "Come on, people: On the path from victims to victors." They make a compelling argument that an epidemic of fatherlessness is destroying too many lives in the ghetto.

The family breakdown, so evident among the poor, seems to be a trend in all of society.

Racism has not disappeared since that awful day 40 years ago. But its blight no longer limits abilities in the widespread way it once did.

King's strategy of nonviolent protest ultimately triumphed over the troubles of his day, but violence remains a scourge in too many American cities. Unless there is a concerted effort among all people to help repair impoverished black families and instill hope, the tensions that exploded in 1968 will continue to simmer just below the surface.