Barack Obama is urging Americans to continue Martin Luther King's pursuit of social and economic justice.
The Democratic presidential candidate made the call during a speech in Indiana today, the 40th anniversary of King's death. Obama says as long as Americans are trapped in poverty and denied fair treatment, King's dream will remain out of reach for many.
He also spoke of another leader gunned down in 1968, Democratic presidential candidate Robert F. Kennedy. The night King was shot, Kennedy was in Indiana, where he made a memorable speech after informing the crowd that King had been killed.
The other 2008 presidential candidates have also been marking the anniversary. John McCain and Hillary Rodham Clinton traveled to Memphis, the city where King died.
McCain said that King's importance is even bigger in America today than it was 40 years ago.