Race and Gender Are Issues in Tense Day for Democrats

After staying on the sidelines in the first year of the campaign, race and to a lesser extent gender have burst into the forefront of the Democratic presidential contest, thrusting Senators Barack Obama and Hillary Rodham Clinton into the middle of a sharp-edged social and political debate that transcends their candidacies.

In a tense day of exchanges by the candidates and their supporters, Mrs. Clinton suggested on Sunday that Mr. Obama’s campaign, in an effort to inject race into the contest, distorted remarks she had made about the Rev. Dr. Martin Luther King Jr.

Mr. Obama tartly dismissed Mrs. Clinton’s suggestion, adding that “the notion that somehow this is our doing is ludicrous.”