By DeWayne Wickham

If there is a lesson to learn from the speech on race that Barack Obama gave last week it is this: It’s a rare moment in the life of this country when a politician is moved by unselfish courage, rather than political expediency, to address the nation.

Obama’s speech was one of those moments. So, too, was the address President John Kennedy gave on June 11, 1963. Earlier that day Kennedy nationalized a unit of the Alabama National Guard to enforce a federal court order to desegregate the University of Alabama.

“That order called for the admission of two clearly qualified young Alabama residents who happened to have been born Negro,” Kennedy said. Shortly after Gov. George Wallace stood in the doorway of a campus building to stop the black students from entering the school, the president ordered the Guard unit into action.

Kennedy could have ended his address with an explanation of his decision to enforce the court order, but he didn’t. Instead, he courageously called on the nation to take a big step forward.

“Today we are committed to a worldwide struggle to promote and protect the rights of all who wish to be free. And when Americans are sent to Vietnam or West Berlin, we do not ask for whites only.” Blacks in this country should be able to not only attend a public school of their choice but also to “receive equal service in places of public accommodation, such as hotels and restaurants and theaters and retail stores,” Kennedy said.

Then he announced he would ask Congress to pass a civil rights bill that guaranteed these rights for blacks. The following year, the Civil Rights Act of 1964 became law.

In 1965, President Lyndon Johnson was driven by courage, not political pandering, to address the nation. On March 15, he appeared before a joint session of Congress to urge passage of the Voting Rights Act. His speech came just a week after non-violent civil rights activists in Selma, Ala., were attacked by law enforcement officers. The chilling images of mostly black demonstrators being knocked to the ground by blasts of water from fire hoses and attacked by police dogs and baton-wielding officers were seen in TV newscasts around the world.

Johnson responded by not only asking Congress to pass the Voting Rights Act, which it did the following year; he connected himself — and his presidency — to the civil rights movement. “Their cause must be our cause, too,” he said of Selma demonstrators. “Because it is not just Negroes, but really it is all of us, who must overcome the crippling legacy of bigotry and injustice. And we shall overcome.”

The speech Obama gave was not in reaction to a great physical assault on the rights of blacks. Instead, it was a response to a far more subtle guilt-by-association attempt to marginalize the black presidential candidate. By not quitting his church of nearly two decades, Obama proclaimed himself a disciple of the warped views of its pastor, the Rev. Jeremiah Wright, critics said.

But in his address, Obama not only rejected Wright’s “profoundly distorted view of this country,” he challenged the rest of us to break the “racial stalemate we’ve been stuck in for years.”

He told blacks to take more responsibility for their own lives and urged whites to acknowledge that discrimination — past and present — continues to plague blacks. That’s not the kind of talk someone who shamelessly seeks political office would give in a nation where fault lines of racial division still run deep.

Obama’s speech was an act of courage that in the short run may put at risk his presidential ambition, but in the long run might save this nation from itself.