Lt. Gov. Bill Halter announced Monday that he will challenge Sen. Blanche Lincoln in the Democratic primary.

In a statement released by his campaign, Halter, one of the most liberal politicians in the state, said he plans to file for the Senate race today.

“Washington is broken. It’s working for the special interests, not Arkansas families,” he said in a statement. “Enough is enough. It’s past time to put more Arkansas values in Washington.”

Halter’s entry into the race was cheered by liberal groups, which had been openly courting the lieutenant governor to take on the moderate Lincoln.

The Progressive Change Campaign Committee, Democracy for America, Daily Kos and MoveOn.org announced that they would work to raise $500,000 for his Senate campaign in the coming week.

More than half a dozen Republicans are vying for the opportunity to take on Lincoln this fall. The leading GOP candidates are Rep. John Boozman and state Sen. Gilbert Baker.

“I know that I am the target of both political extremes but that’s what makes this campaign so important to all of us,” Lincoln said in a statement released by her campaign. “This Senate seat belongs to Arkansas, not to outside groups that are angry I don’t answer to them.”