Updated

MARION, Ark. - Tuesday's Senate primaries in Arkansas are shaping up as key tests of voter discontent -- with candidates on both sides under attack.

Two term Senator Blanche Lincoln and Republican Congressman John Boozman, the frontrunner for the GOP nomination, both face party rivals running as outsiders.

Lincoln is fighting off the insurgent candidacy of Democratic Lt. Gov. Bill Halter, who is trying to attach himself to the wave of anti-Washington sentiment that has swept across the country.

In January, Democrats lost the Senate seat in Massachusetts long held by the late Edward M. Kennedy. Three-term Sen. Robert Bennett was recently ousted at a Utah Republican party convention, and a few days later, five term Rep. Alan Mollohan, D-W.Va., lost his primary.‬

"If you send the same people back to Washington, you're guaranteed to get the same result," Halter said. "The message of change for Washington is definitely resonating. People are frustrated with what's going on in our nation's capitol."

Sen. Lincoln recognizes the challenge. "I know that people are very disappointed in Washington and quite frankly I am too in a lot of ways," she said.

For months Lincoln has been considered one of the most vulnerable incumbents heading into the 2010 midterm elections. Much of the anger dogging Lincoln in Arkansas has centered around the health care debate.

Lincoln angered Republicans by supporting the Democratic-led health care overhaul and at the same time raised the ire of liberals for her opposition to a government-run public insurance option.‬‪
  
"It's not who wins or loses the vote at the end of the day, it's whether or not we're solving the country's problems, and that's what Arkansans want. They want results." Lincoln told Fox News on Monday.

Her two challengers have spent millions flooding the airwaves with negative attack ads, with national labor unions pouring money into attacks.

"It's tough when people come in and misrepresent your record and spend three and four times the money you have to spend to do just that," Lincoln said.

Lincoln has decried the negative tone of the race, however, she also has launched blistering ads against her opponent, calling Halter "Dollar Bill" for working at a company accused of outsourcing U.S. jobs to India.

"I think most folks are really more interested in things you want to do for the state than tearing down somebody else," Halter said.

However, the Halter campaign has also played into the bitter discourse by releasing ads dubbing Lincoln "Bailout Blanche" for her votes for TARP, the Troubled Asset Relief Program.

Meanwhile, Rep. Boozman has been leading the polls among Republicans for months. However, lately Boozman has been targeted as a Washington insider by the two candidates aiming for at least a spot in a June 8 runoff.‬‪

Republican challengers Gilbert Baker and Jim Holt, both with experience in the state Senate, have spent the final stages of the race painting themselves as outsider candidates running against Washington.

There are eight candidates running for the Republican nomination and most admit it is likely to result in a June 8 runoff between the top two.

The Democratic race also has a distinct possibility of heading to a runoff because of the third candidate. Local businessman D.C. Morrison is a conservative Democrat who has polled just below 10 percent, enough to potentially force Lincoln and Halter to a June 8 runoff election.

Lincoln told Fox News she's ready for a runoff. "You can't assume you're going to win and you can't assume you're going to win without a runoff," she said.

Halter aides say they're planning on winning the nomination Tuesday night, but privately they acknowledge they're also planning for bruising three-week runoff campaign.