(CNN) -- While Sen. Hillary Clinton won a majority of Michigan Democratic primary votes Tuesday, blacks and the youngest voters favored the "uncommitted" choice.
Sen. Hillary Clinton did not remove her name from the ballot in the Michigan Democratic primary.
According to CNN exit polling, 68 percent of blacks chose uncommitted, compared with 30 percent for the Democratic front-runner.
Forty-eight percent of all voters ages 18-29 voted uncommitted, compared with 43 percent for Clinton. The former first lady took more votes than uncommitted in all other age groups; the older the voters, the wider the margin was.
The racial disparity could be a bad sign for Clinton going into the South Carolina primary, where half of all Democratic voters are black.
Clinton and Sen. Barack Obama -- along with their surrogates and supporters -- have been engaged in bickering since last weekend over comments Clinton made about President Lyndon Johnson's contributions to the Civil Rights movement.
Some African-American leaders criticized the remarks as dismissive of the civil rights movement and of King. On Sunday, Obama described Clinton's comments as "ill-advised" but rejected any suggestion that his campaign has been behind the complaints.
By Monday, both candidates were calling for a truce.
Clinton was the only top-tier presidential candidate on the ballot in the Democratic primary, and she carried 58 percent of the overall vote, while 37 percent of the voters in the Democratic primary chose to vote uncommitted.
Michigan's decision to move its primary to January 15 angered national Democratic Party officials who were trying to slow the "front-loading" by states of the primary process.
Obama of Illinois and former North Carolina Sen. John Edwards withdrew from the ballot as a show of solidarity, leaving a ballot of Clinton, Rep. Dennis Kucinich of Ohio, former Sen. Mike Gravel of Alaska and Sen. Chris Dodd of Connecticut, who later withdrew from the race.
Under state law, supporters of other candidates could not cast write-in votes for them.
Some Democratic leaders had urged Obama and Edwards supporters to vote "uncommitted" as a sign of support for their candidates.
If at least 15 percent of the voters in a congressional district opt for "uncommitted," delegates not bound to any candidate could attend the national convention.
That could allow supporters of Edwards or Obama to play a role in candidate selection -- if the national party changes its mind and decides to count Michigan's delegates.
"The bottom line is the Clinton people have managed to circumvent the process," former Michigan Sen. Don Riegle -- an Obama supporter -- told The Detroit News.
"Democrats should show there is a large number of people who don't like the railroad job they're trying to do for Hillary Clinton," he said.
A new group, Detroiters for Uncommitted Voters, started a grassroots campaign to promote the "uncommitted" option.
Democratic Rep. John Conyers and his wife, Detroit City Councilwoman Monica Conyers, said they would launch ads calling for "uncommitted" votes if there was no other way to register support for Barack Obama, The Detroit News reported last week.
The option was also endorsed by Sen. Carl Levin of Michigan and state Democratic Party Chair Mark Brewer as a way for Democrats who do not support Clinton to participate in the vote.
Neither man has endorsed a presidential candidate.
In 2008, more than in recent campaigns, the delegate count may prove important.
Narrow losses -- which still add to a candidate's delegate total -- could keep more than one hopeful in contention. "For the first time since 1988, this is a delegate race," Clinton aide Howard Wolfson said last week. E-mail to a friend
CNN's Rebecca Sinderbrand contributed to this story.
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