Arkansas Democrats may make Sen. Blanche Lincoln the latest casualty of this year's anti-Washington attitude.
Lincoln faces Lt. Gov. Bill Halter in a Democratic runoff because neither garnered 50 percent of the vote in the state's May 18 primary.
The two have spent more than $10 million on the campaign, mostly on campaign advertising attacking each other.
The winner will face Rep. John Boozman, the Republican nominee, who so far leads both candidates in the polls.
While moderate Lincoln won more votes in the primary, Halter, running to her left, appears to have a slight lead, likely aided by the labor unions that are backing him with millions of dollars in television and radio advertising.
Lincoln on Monday began wrapping up a "Countdown to Victory" tour across about two dozen counties that began with a boost from former President Clinton, who stumped for her last week in Little Rock.
Liberal groups backing Halter struck back after the Clinton appearance, airing an ad that likens Halter, not Lincoln, to Clinton, who served three terms as Arkansas governor.
Halter, meanwhile, is finishing a "Countdown to Change" tour across the state.
Both candidates hope to pick up support from the 13 percent of voters who chose conservative Democrat D.C. Morrison in the primary.
"When it is that close, people start to reason differently, so those Lincoln voters who voted for her because they didn't think Halter had a chance of winning are now rethinking that," said Janine Parry, director of the Arkansas Poll at the University of Arkansas.