Faced with a primary challenge from Arkansas' lieutenant governor, Democratic Sen. Blanche Lincoln found herself in the precarious position Monday of fending off angry liberal activists on the left as well as conservative Republicans on the right in her effort to keep her seat in the Senate.
Lincoln, who is considered one of the Senate's most vulnerable incumbents, was pressed to address the new Democratic threat hours after Lt. Gov. Bill Halter announced he would challenge her in Arkansas' May 18 primary.
The development means that Lincoln could now have two of the party's most formidable campaign forces, the liberal group MoveOn.org, and organized labor working against her. After Halter's announcement, the AFL-CIO's political committee voted to endorse him, according to a union official. Three unions had already pledged $3 million to help Halter's campaign.
Meanwhile, President Barack Obama's effort to defend Lincoln and other threatened incumbents continues to run into trouble. Two other vulnerable Democrats have drawn primary challenges — Sens. Arlen Specter in Pennsylvania and Michael Bennet in Colorado — despite White House attempts to clear the field for them. And Sen. Kirsten Gillibrand in New York may soon find herself in a primary fight against former Rep. Harold Ford Jr.
Lincoln indicated that she will cite the attacks from both flanks as a reason for voters to support her.
"Outside special interests on both extremes are plotting today to gain control of this Senate seat representing you, the people of Arkansas," Lincoln told supporters at her campaign headquarters before filing for re-election. "I know it, because I am the rope in the tug of war, folks."
Supporting her rhetoric was the scene at Arkansas' state Capitol as she filed re-election papers. As Lincoln faced questions over Halter's primary challenge from the left, a dozen conservative protesters waved signs and yelled "Bye-bye, Blanche."
Halter, who was elected to the state's No. 2 spot in 2006, responded to months of public courting by liberal groups angry with Lincoln's stances on health care, labor and air pollution regulations.
Lincoln has vowed to oppose any effort by Democratic leaders to push a health care bill through the Senate using special rules and a simple majority vote. But the challenge from Halter, who has the backing of progressives, could force her to rethink her position.
"Washington is broken. It's working for the special interests, not Arkansas families," Halter said in a statement released Monday morning.
In key states, declared and undeclared Democratic primary challengers are hoping to seize on anti-incumbent sentiment that's running strong across the electorate. In Washington, Democratic Party officials fear that primaries will weaken the eventual nominee ahead of the November general election, and they have sought to minimize the number of primary races, particularly in the Senate.
Republicans said they believed the primary fight between the Democrats would help them by forcing the two-term senator to spend more of the $5 million she has in the bank for her re-election bid.
"I was thrilled to hear the news ... I think the obvious thing is it's going to require Senator Lincoln to spend some of that war chest she's amassed," said Curtis Coleman, a North Little Rock businessman who filed to run for the post. Other Republicans who filed to run for Lincoln's seat Monday included Fred Ramey of Searcy and Congressman John Boozman.
Eight Republicans have announced interest in the Senate seat as Lincoln's popularity waned in the GOP-leaning state.
Privately, a Democratic official close to Lincoln worried that the primary challenge would drain her financial resources. The only good is the race could clearly cast her as a moderate, the official said.
Halter, a one-term lieutenant governor, is a former Clinton administration official, having served as a deputy commissioner and acting commissioner of the federal Social Security Administration. He was elected lieutenant governor in 2006 after briefly considering a run for governor against Mike Beebe, who won the post.
The liberal group MoveOn.org, which had urged Halter to challenge Lincoln, asked its members to support his primary challenge to Lincoln. The Service Employees International Union in December said it would help Halter retire his debt from his 2006 lieutenant governor campaign, and the labor union's head said then he believed Halter had an "extremely bright political future."
The AFL-CIO is expected to approve later this week its political committee's endorsement vote for Halter. A union official said the federation hopes to raise $5 million for Halter's campaign.
Lincoln has opposed key union-organizing legislation and Obama's nominee for the National Labor Relations Board. Both positions have gained the ire of the Arkansas AFL-CIO, which backed her re-election bid six years ago.
As a lieutenant governor who hasn't cast a vote in the state Legislature, Halter's position on health care and other issues remains unknown. His signature issue has been his advocacy of an amendment authorizing the state to sell lottery tickets to raise money for college scholarships, which was approved by voters in 2008.
Lincoln declined to say whether she believed Halter represented the left's extreme.
"I think people are going to ask Mr. Halter where he is on things, and he's going to have to answer to that," Lincoln told reporters.
The Senate landscape has shifted since the year began, with several states now considered competitive because of unexpected Democratic retirements.
Republicans would need to hang on to all of their seats — which is far from a certainty — and pick up 10 Democratic-held seats to take control of the Senate. Aside from Lincoln, the GOP also is going after Democratic incumbents in Nevada, Pennsylvania and Colorado. Republicans would add New York to that vulnerable Democrat list if they could just find a candidate to challenge Gillibrand. The GOP also is making strong plays for open Democratic-held seats in Illinois, Delaware, Connecticut, Indiana, and North Dakota.
AP National Political Writer Liz Sidoti in Washington contributed to this report.
© Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.