Sanders accuses Republicans of racism

WASHINGTON - Democratic presidential candidate Bernie Sanders accused Donald Trump and other Republican politicians Tuesday of mounting a "racist" effort to try to "delegitimize" President Barack Obama.

Appearing at a townhall-style forum on CNN, Sanders said Obama critics' questioning of the president's birthplace was part of what he called "continuous and unprecedented obstructionism" in Washington.

Trump helped lead the drive to raise doubts about Obama's citizenship in what is known as the "birther movement." "You can disagree with Obama all you want," Sanders said, "but to say that the president of the United States, who won an election fair and square, was not a legitimate president, really undermines what we are as a nation."

"Do I think at least in some parts of that Republican base there is race involved in that?" he added. "Absolutely. Absolutely." The campaign event took place in South Carolina, which holds its Democratic primary election Saturday.

Sanders, a self-described Democratic Socialist who is calling for a "political revolution," has astounded the political establishment with a surprise challenge to frontrunner Clinton.

But he faces a major obstacle trying to win over African American voters, who make up a large part of the electorate in South Carolina.

His Democratic rival Hillary Clinton, who leads in the polls in the state, hopes a victory will put her well ahead in the race to win the Democratic nomination before November's presidential election.

She appeared separately at the CNN forum.