About two dozen members of Congress are co-sponsors of legislation to create a commission that would study reparations - that is, payments and programs to make up for the damage done by slavery.
The National Association for the Advancement of Colored People supports the legislation, too. Cities around the country, including Obama's home of Chicago, have endorsed the idea, and so has a major union, the American Federation of State, County and Municipal Employees.
Obama has worked to be seen as someone who will bring people together, not divide them into various interest groups with checklists of demands. Supporting reparations could undermine that image and make him appear to be pandering to black voters.
"Let's not be naive. Senator Obama is running for president of the United States, and so he is in a constant battle to save his political life," said Kibibi Tyehimba, co-chair of the National Coalition of Blacks for Reparations in America. "In light of the demographics of this country, I don't think it's realistic to expect him to do anything other than what he's done."
But this is not a position Obama adopted just for the presidential campaign. He voiced the same concerns about reparations during his successful run for the Senate in 2004.
There's enough flexibility in the term reparations that Obama can oppose them and still have common ground with supporters.
The NAACP says reparations could take the form of government programs to help struggling people of all races. Efforts to improve urban schools could also aid students in the mountains of West Virginia, said Hilary Shelton, director of the NAACP's Washington bureau. "The solution could be broad and sweeping," he said.
The National Urban League, a group Obama addressed yesterday without mentioning the issue in his speech, avoids the word reparations as too vague and highly charged. But the group advocates government action to close the gaps between white and black America.
Urban League President Marc Morial said he expects his members to press Obama on how he intends to close those gaps and what action he would take in the first 100 days of his presidency.