AFL-CIO President Richard Trumka said Tuesday he would be "highly surprised" if his union federation's state chapter supported Sen. Blanche Lincoln (D-Ark.) if she won her runoff against Lt. Gov. Bill Halter (D).

The labor movement has invested millions in defeating Lincoln by canvassing the state and running television ads.

Lincoln has ended up on the wrong side of unions — traditional Democratic allies — for her opposition to legislation that would make union organizing much easier, as well as being against a government-run health insurance program. 

Trumka said the decision to endorse Lincoln, if she emerged victorious on Tuesday, would be up to AFL-CIO members in Arkansas. "That is a decision that our members on the ground make. I would feel highly surprised if they were to do that," Trumka said.

While the AFL-CIO has not committed to not supporting Lincoln if she did win Tuesday, at least one powerful labor group has pledged not to help her in the fall.

The Service Employees International Union, another Halter supporter, has said that they would not endorse Lincoln if she was the Democrats' general election candidate.

The union leader also said he thought Halter would prevail Tuesday in his challenge against Lincoln.
"I think Halter wins tonight and I think he ultimately goes on and wins in the fall. If I didn't believe that, we would probably have not been in the race," Trumka said.