Columbia, South Carolina - Barack Obama lashed out at rival Hillary Clinton's husband Bill Monday, calling the former president's role in the race for the Democratic presidential nomination "pretty troubling."
"You know, the former president, who I think all of us have a lot of regard for, has taken his advocacy on behalf of his wife to a level that I think is pretty troubling," Obama said in an interview with ABC's "Good Morning America."
"I understand him wanting to promote his wife's candidacy," Obama said. "She's got a record that she can run on.
"But I think it's important that we try to maintain some ... level of honesty and candor during the course of the campaign. If we don't, then we feed the cynicism that has led so many Americans to be turned off to politics."
The comments came as Bill Clinton has stepped up his hard-charging tactics on behalf of his wife, and ahead of a televised debate between the two Democratic campaign leader, along with third-runner John Edwards, Monday night.
With Hillary Clinton holding a lead in national polls over her fellow senator, Obama attacked Bill Clinton's rising profile in the campaign and specifically referred to two recent and controversial moves by the former president: his much-publicized "fairy tale" comment about Obama's position on the Iraq war, and his efforts to prevent Nevada's Democratic party from holding caucuses last Saturday inside Las Vegas casinos -- a move the Clinton campaign feared would help Obama.
"He continues to make statements that are not supported by the facts -- whether it's about my record of opposition to the war in Iraq or our approach to organizing in Las Vegas," the US senator from Illinois continued.
Senator Clinton was Monday headed to South Carolina for the next contest in the 2008 Democratic nominating race and to pay homage to civil rights icon Martin Luther King, on the public holiday honoring his birth.
She, Obama and Edwards will clash in a two-hour televised debate in the coastal resort of Myrtle Beach, three days after she captured the Nevada caucuses.
On a perilous fault line of race and politics, the former first lady and the Obama, hoping to be America's first black president, delicately renewed hostilities Sunday before the January 26 South Carolina primary.
For Clinton, the contest is a chance to appeal to African Americans in the state and nearly two dozen others which vote on the closely contested Democratic race in a blitz of contests on "Super Tuesday," February 5.
For Obama, South Carolina is close to a must-win encounter. It is also his first chance to benefit from a large turnout of African-Americans, in a unique position as the first black candidate with a realistic hope of the presidency.
Both Clinton and Obama attempted to symbolically frame the week of campaigning Sunday by wooing African American worshippers.
Obama made a symbolic appearance in Atlanta's Ebenezer Baptist Church, the launch pad for King's crusade.
Clinton meanwhile garnered an endorsement from an influential black minister in Harlem, New York City.
Tensions will be especially acute, as only last week Clinton and Obama smoothed over a row triggered by her remarks about King, considered offensive by some in the black community.
A Mason Dixon survey Thursday for South Carolina's State newspaper of likely Democratic primary voters gave Obama support of 56 percent of African Americans, compared to 25 percent for Clinton and two percent for former senator John Edwards.
Among whites, Clinton led with 39 percent, Edwards had 28 percent and Obama 20 percent.
According to a RealClearPolitics.com average, Obama has a 10 percent lead in South Carolina polls among all Democrats.
Republicans, meanwhile, turned their attention to Florida, which holds its primaries on January 29.
In contrast with previous contests, the winner in Florida will take the entire batch of 57 delegates to the Republican Party's convention, which could provide a significant boost to any of the leading four candidates: John McCain, Mitt Romney, Mike Huckabee and Rudy Giuliani.
"The Republican race is a dead heat with all four major contenders within three points for first place," said Peter Brown, assistant director of the Quinnipiac University Polling Institute.
"Giuliani is showing the negative effects of poor finishes in Iowa and New Hampshire, while McCain's jump is not unexpected given his New Hampshire victory."
The survey, taken in mid-January, shows McCain at 22 percent, Giuliani at 20, and Romney and Huckabee at 19.
© 2008 Agence France Presse