[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/03/17/art.lincoln.gi.jpg caption ="Sen. Blanche Lincoln and union activists are at odds in new television ads."]
Washington (CNN) - Arkansas Sen. Blanche Lincoln is casting herself as an "independent voice" in her Democratic primary fight against Lieutenant Gov. Bill Halter, who has the backing of unions and liberal activists frustrated with Lincoln's moderate positions.
Just this week, Lincoln launched a new television ad taking aim at the "bunch of Washington D.C. unions" running ads accusing her of siding with big business over middle class workers. A union-backed group called "Arkansans For Change" is behind those ads.
"I'm not working for them," she tells viewers in her response ad. "I work for you."
One union, the Arkansas AFL-CIO, is now hitting back at Lincoln for that claim, calling her "a hypocritical, flip-flopping D.C. politician." The group has endorsed Halter.
"It's easy for her to try to paint opponents as outsiders, but working class voters in Arkansas can see as well as anybody that she has turned her back on us," Arkansas AFL-CIO President Alan Hughes said in a statement Wednesday.
"Only someone who has become a career politician in Washington DC could spend ten years asking for our support, take hundreds of thousands of dollars from blue collar workers, then turn around and attack us as 'outsiders' because we wouldn't help her this time around," he said.
Unions and liberal activists, many of them from out of state, began lining up behind Halter this year after Lincoln refused to back a public insurance option in the health care reform bill. Lincoln also voted for CAFTA - the free trade agreement between the U.S. and Central American countries - which is not exactly a favorite piece of legislation among workers.
The AFL-CIO noted that Lincoln welcomed its endorsement during her 2004 campaign. "I'm honored to receive the endorsement today from the Arkansas AFL-CIO for my work in the Senate to improve the lives of Arkansas working families while fighting to keep our jobs from going overseas," she said at the time.
A spokesman for Lincoln's campaign did not respond to a request for comment.