US President Barack Obama's mere presence at the ceremony celebrating the anniversary of the March on Washington will embody the fulfilled dreams of thousands who rallied at the same place 50 years ago for racial equality and personify the continued struggle for that elusive goal.
When he became president, Obama blasted through a heavy barrier that many before him had only pushed against. But his presidency has been marred by racist backlash and his administration has found itself refighting battles already thought won, such as ensuring equal access to the polls.
Obama is expected to speak on Wednesday just after an organised ringing of bells by churches and others at 3pm, the time when the Reverend Martin Luther King Jr delivered his spellbinding "I Have a Dream" speech.
Obama will be joined by former Presidents Jimmy Carter and Bill Clinton at the memorial's steps. Other luminaries include Lynda Bird Johnson Robb, daughter of President Lyndon Johnson, who signed the 1964 Civil Rights Act and the 1965 Voting Rights Act.
A march led by a replica of a transit bus that civil rights leader Rosa Parks rode when she refused to give up her seat to a white man in 1955 and an interfaith service also were planned for Wednesday morning. A march held on Saturday drew tens of thousands to the Lincoln Memorial.
Obama considers the 1963 march a "seminal event" and part of his generation's "formative memory". A half-century after the march, he said, is a good time to reflect on how far the country has come and how far it still has to go.
