Richard Mourdock, 2012's Low-Key Tea Partier

PHOTO: Indiana State Treasurer Richard Mourdock answers a question during a news conference on Thursday, March 22, 2012, in South Bend, Ind.James Brosher/South Ben Tribune/AP Photo
Indiana State Treasurer Richard Mourdock answers a question during a news conference on Thursday, March 22, 2012, in South Bend, Ind.

What do you get when the Tea Party's anger simmers away?

You get Richard Mourdock, the low-key fiscal conservative who's challenging Sen. Richard Lugar, the longest-tenured Republican in the U.S. Senate. The GOP senate primary in Indiana takes place May 8.

"I am a very even-keeled guy," Mourdock told ABC News in an April interview. "Mr. Lugar is trying to paint me as this wild-eyed Tea-Party guy. It's not like I just popped up like a morel mushroom in the spring of agitation."

Indeed he didn't. After a career in business, Mourdock was first elected state treasurer in 2006, debatably a better year for Democrats than 2008. Now, after that spring of agitation, he's been endorsed over Lugar by Sarah Palin, influential conservative blogger Erick Erickson, Congresswoman Michelle Bachman, D.C. conservative groups FreedomWorks and the Club for Growth, the American Conservative Union, the National Rifle Association, Citizens United, Tea Party Express, and Grover Norquist.

Mourdock is running, he says, because a handful of Indiana Republican State Committee members asked him to, a surprise to Mourdock given Lugar's long standing. "People started saying to me, 'It's time,'" Mourdock said. "I heard it many times: He has a Washington view and not a Hoosier view."

Lugar's supporters have sprung to his defense, most notable among them Gov. Mitch Daniels, the American Action Network, a D.C.-based 501(c)4 group founded by former Minnesota Sen. Norm Coleman and run by GOP fundraising luminary Fred Malek. Two super PACs have formed in 2012, one in D.C. and another in Sacramento, for the purpose of attacking Mourdock. The Young Guns Network, a 501(c)4 group formed by former aides to House Majority Leader Eric Cantor, is supporting Lugar with TV ads as part of a campaign on energy and conservation.

As a result, Indiana's Senate primary has become a proxy battle between the GOP's establishment and its Tea-Party wing. Last week, eight outside groups had spent nearly $2.2 million; since then, two more groups have gotten involved, and outside spending totals nearly $4.3 million.

Conservatives see Indiana as the latest battleground in the war over Republican Party identity, a chance to unseat one of the final old-guard senators who upholds such traditions as earmarks and working with Democrats. The race bears the mark of every Tea-Party-vs.-establishment primary in 2010: A conservative candidate arises, is backed by national groups (both the "grassroots" PACs and the TV-ad-funders), and Republicans enter an affair with a candidate deemed ideologically pure--one who may or may not change Washington.

Mourdock's supporters have outspent Lugar's $2.6 million to $1.6 million. As of March 31, Lugar had spent $5.1 million to Mourdock's $1.7 million. With news that Lugar's largest backer, the American Action Network, canceled $200,000 worth of air time, the possibility of Lugar's demise looks even more real.

With Mitt Romney as their presidential standard bearer, and with Sen. Orrin Hatch having learned from the downfall of last year's Tea-Party casualty Bob Bennett in Utah, Mourdock offers Tea Partiers their best chance for a high-profile primary coup in 2012.

One thing is certain: If Lugar loses, Maine's Susan Collins will be the only centrist, bipartisan Republican senator left.

Part of why Mourdock seems so even-tempered is the opponent he's running against. "Every time [Lugar] defined himself as a conservative, there was a part of me that was just ready to jump, and said, 'Go get him! Attack! Attack!" Mourdock said about his one debate with Lugar, held in early April. "I listened to the better angel of my nature. I can't attack this grandfatherly figure in Republican politics."

At least not personally, or in person.

The race has been characterized by attack ads, both from outside groups and the candidates, but as The Washington Post's Melinda Henneberger has written, they've not been particularly mean. While some have centered on policy, impugning Lugar's record in grave tones, at times they've amounted to vapid finger-pointing over opaque research nuggets.

Mourdock's campaign has called Lugar "Obama's favorite Republican," a reference to a still-frame of Lugar that appeared in a 2008 campaign ad highlighting Obama's bipartisan work on nuclear nonproliferation. The Club for Growth's ads have focused on Lugar's support for bailouts (Lugar voted for TARP, along with 30 other GOP senators, and the auto bailout pushed by President Bush) and his vote against an earmark moratorium; the latest accuses him of "clinging to power."

In February, Lugar began airing ads about "Mourdock failing to show up for his taxpayer-funded job 66 percent of the time." More recently, Lugar's campaign hit Mourdock for supporting the Fairness Doctrine in a 1992 run for Congress. The pro-Lugar super PAC Hoosiers for Jobs was formed in Sacramento in February, seemingly for the lone purpose of attacking the Club for Growth: its two TV ads devote more attention to the Club and its president, former Indiana Rep. Chris Chocola, than to either Lugar or Mourdock.

Perhaps the most controversial ads came from Lugar's campaign and American Action Network, which accused Mourdock of taking an "illegal" tax break--a second homestead exemption--which Mourdock says was an error by the county assessor, carried over from the house's previous owner, which Mourdock discovered and insisted on paying three years' worth of back taxes. Mourdock called on both Lugar and AAN to pull the ads.

Mourdock epitomizes the Tea Party's current, relatively mellowed iteration in that he wants to dismantle parts of the federal government--"Let's do away with the Departments of Education, Energy Commerce, Housing and Urban Development," he said, calling for sunset provisions for every agency--and has pressed legal action against the administration, all without the bombast of the right's 2010 crop of candidates.

Well before a cadre of anti-"Obamacare" attorneys general made suing the administration vogue, Mourdock was the leading opponent of Chrysler's bankruptcy and sale to Fiat, which were prompted by Obama. Mourdock sued on behalf of Indiana state-worker pension funds to which Chrysler owed money, protesting they'd been given short-shrift in Chrysler's debt repayments and taking his case to the doorstep of the Supreme Court. The court delayed the sale, but declined to hear Mourdock's case upon review and ultimately allowed the Fiat purchase.

Mourdock symbolizes something else about the GOP's trajectory: His establishment-backed opponent sounds an awful lot like a Tea Partier. Lugar and Mourdock both support reforms to Medicare along the lines of what Rep. Paul Ryan, R-Wis., has suggested, and both say they want to reengineer Social Security benefits for younger people. Lugar touted his votes for Ryan's last budget, which infuriated the left and center. In their lone debate, the two men seemed to agree on almost everything, save ethanol subsidies (Mourdock opposes them) and aid to Russia (Mourdock suggested money for Russia just means more money for Iran).

The highest-profile issue in this race hasn't been policy, but Lugar's residence: Lugar is so vulnerable partly because he hasn't lived in the state for years, had to repay the U.S. Treasury after billing taxpayers for hotel bills during his trips back to Indiana, and was temporarily ruled ineligible to vote in the county where his driver's license was issued. None of that has looked very good, and it underpins Mourdock's oblique references to Lugar's "Washington view," as well as his comments, at the very end of their debate: "The first thing I'm going to do to represent Hoosiers is to be in touch with them. I'm proud to call this state home. ... It is a place that if I have the privilege of serving as your U.S. senator, I'm not moving from. I will always call Darmstadt, Indiana, home."

On its own, Lugar's residence issue probably wouldn't be enough to sink him. Facing the same issue, other Indiana politicians have had it much worse: Coats won his multi-way primary and a Senate seat despite a cluster-bomb of attacks over his lobbying career and his comment, made earlier that year, that North Carolina might be a "better place" than Indiana.

But the residency issue has given Mourdock, FreedomWorks, and the Club for Growth a capstone that ties together the same attacks they leveled against nearly every candidate they opposed in 2010, cast this time in a new light. Lugar, 80, supported bailouts and the DREAM Act and opposed an earmarks ban because he's out of touch with Indiana--because he hasn't been living there, they say.

"He checked out, he logged off Indiana a long time ago, which is why he's in the trouble he's in," Mourdock said.

Mourdock, known to be omnipresent at GOP county events and Lincoln Day dinners, has played up his availability. "I have this incredible base," he said, counting "three quarters of the county chairmen" on his side. He also lists, among his credentials, Indiana's relative fiscal health (in November, it carried the third lowest debt per capita) while other states' balance sheets tanked during the recession--a bullet point that fits well within his campaign narrative as a treasurer by trade, although it's maybe dubious how much credit Mourdock can take for Indiana's spending and revenue policies.

So what's the difference between these two men, other than their addresses? If Lugar now checks the conservative boxes on budgeting and entitlement reform, what exactly is Mourdock offering? Why vote for him?

There is no doubt that Mourdock is more conservative than Lugar. He wants to slash budgets further, and he said the Ryan budget plan, of which Lugar is an avowed fan, does not go far enough in its cuts. Last year, Mourdock offered his own budget plan, which he admits was "rather rudimentary," that included $7.6 trillion in cuts. (In a YouTube video, Lugar's campaign highlighted one analyst's opinion that Mourdock's budget was "too kooky for words.") He expressed reservations about voting for a debt-limit increase without more significant concessions from Democrats.

And Mourdock is expected to be a weaker candidate against Democratic Rep. Joe Donnelly in the general election. No major polls have been taken in Indiana to back up that conventional wisdom, but Donnelly's campaign is much more sanguine about the possibility of facing Mourdock than Lugar.

The common thread in Mourdock's (and his supporters') complaints against Lugar has to do with his willingness to go along with non-conservatives. His votes for bailouts at the dire urgings of the Bush administration, his vote to approve Supreme Court Justice Sonia Sotomayor, his partnership with Democrats (Obama included) on nuclear nonproliferation legislation, and his support for earmarks all smack of how the Senate used to be, when lawmakers made concessions on judicial appointees and worked across party lines for the sake of keeping things moving.

That's the essence of how Tea Party lawmakers have changed the culture of the Capitol, as House Speaker John Boehner found out in trying to broker a debt-limit compromise last year.

If elected, Mourdock that's what Mourdock will offer.

"There was a day when it was exactly the right thing to do. When Dick Lugar went in, there was some of that, but it's not that way now," Mourdock said, when I asked him if there isn't something to be said for compromise.

"Bipartisanship has taken us to the brink of bankruptcy. We don't need bipartisanship, we need application of principle. We are at a historical moment when the two sides are so polarized," Mourdock said. "I'm more frustrated with Republicans than Democrats."

Lugar may not be a wild-eyed Tea Partier, but FreedomWorks and the Club for Growth--the same groups that funded 2010's primary uprisings--will get the same thing out of it if he wins.