BOISE - On the campaign trail, Republican House candidate Marvin "Chick" Heileson calls U.S. Rep. Mike Simpson a liberal who ditched his 1998 pledge never to raise taxes, backed the 2008 bank bailout and supported lifting the debt ceiling, leading to $15 trillion in spending.

Simpson, according to Heileson, is an embarrassment to Idaho.

The thing is, this is the identical tea-party influenced message Heileson was touting ahead of the 2010 primary, when Simpson beat him 58 percent to 24 percent. Heileson at the time questioned whether Simpson was "reading the Constitution of the Soviets."

So what's changed over the past two years that Heileson now thinks Simpson has become vulnerable to the same criticisms?

For one, Heileson, a retired 66-year-old contractor, won't have to split his votes with two other GOP challengers in the primary, the case in the 2010 race. And he thinks voters are growing more aware of what he calls Simpson's free-spending ways.

"There are people who like his record, and people who do have the privilege of voting for him," Heileson said. "But I'm offering something different. I'm not running against him because I want to be a congressman. I'm running against him because of what he is and what he does. That's it."

Among other things, Heileson favors phasing out Social Security, doing away with the U.S. Department of Education and ending foreign aid.

Simpson's status as a seven-term Republican congressman who heads up the House Appropriations' Interior and Environment Subcommittee makes for a formidable rival, even if Heileson's libertarian appeal will find some resonance among voters in Idaho's 2nd District, covering the state from Boise eastward to the Wyoming and Montana borders.

Simpson said America needs lawmakers willing to make tough choices - but also work together with Democrats - for long-term solutions, especially against the daunting challenges that Congress faces: Efforts to cut the nation's $15.7 trillion debt, the Jan. 1 expiration of President Bush-era tax cuts as well as the payroll tax holiday, even looming reductions in Medicaid payments to doctors, to name a few.

"Members of Congress need to be serious legislators," said Simpson, a 61-year-old who left his dentist practice in Blackfoot for Congress in 1998. "What you don't need is someone who is just more partisan, more ideological, somebody unwilling to work across the aisle."

Simpson is also irritated by Heileson's insistence that he's raised taxes.

"You know, taxes are lower today than they were when I took office," he said. "He says a lot of stuff. A lot of the stuff he says just isn't so."

Simpson concedes Heileson's election night tally will likely exceed two years ago.

In addition to the less-crowded partisan field, Simpson is uncertain if the closed GOP primary, where Republicans must openly register their party affiliation for the first time to vote, will discourage moderates who may have sided with him in the past.

"You don't know who is going to turn up to vote," Simpson said. "I take every race seriously, I do what I can to get the vote out, and this is no different."

Simpson has ramped up his fundraising.

In his May 2 report to the Federal Election Commission, he reported $760,000 for the election cycle, easily topping the $474,000 his campaign collected for the same period in 2010.

It's hard to tell Heileson's totals; he missed the filing deadline, as he also did two years ago, when he was hit by a $990 FEC fine for missing the July quarterly report. Heileson said he's brought in about $50,000, compared to $115,000 two years ago.

He downplayed the significance of the tardy report, calling it the oversight of a campaign staffer that he plans to rectify.

"My poor accountant," Heileson said. "He's three days late, and we got accused of hiding our financial reports."

Simpson suggested his rival take it more seriously.

"For someone who always wants to follow the law and the Constitution, I find it ironic," Simpson said.

"When I was a little kid, I used to blame everything on my brother. But sooner or later, you realize you have to take some of the responsibility for yourself."

The two candidates debate Sunday at 7 p.m. on Idaho Public TV