WASHINGTON -- The Tea Party may be looking at its biggest upset yet Tuesday, when voters in Indiana are set to go to the polls in the first tough primary of Sen. Dick Lugar's (R-Ind.) long career. At least, Democrats hope so.
More than a year ago, when state Treasurer Richard Mourdock announced his intention to take on the iconic Lugar, Democrats hoped he would be the next Sharron Angle or Ken Buck -- Tea Party candidates who triumphed in primaries over more mainstream candidates, but who proved unpalatable to the general electorate. Angle's win allowed Senate Majority Leader Harry Reid (D-Nev.) to keep his job. Sen. Michael Bennet (D-Colo.) eked out a 1 percent win over Buck.
Indiana is a little different in that Democrats do not have an incumbent defending a seat, but they do have conservative Rep. Joe Donnelly trying to advance to the upper chamber -- a step up that few imagined he would make facing the entrenched and popular Lugar. So Democrats watched Mourdock -- a statewide officeholder -- with interest.
They were disappointed by what they saw. Mourdock raised very little money early on, and showed little campaign skill. "I just gave up. I mean, there was no way Dick Lugar wasn't going to beat this guy," said one Democratic operative who spoke anonymously to avoid providing ammunition for the GOP campaigns.
But then Lugar ran a spectacularly bad campaign in which he seemed to confirm Mourdock's charge that the senator was out of touch. Lugar was trailing Mourdock by 10 points in the most recent poll.
"It started over a year ago when sort of out of nowhere, in my view, Mourdock announced he was going to run on a Tea Party ticket," said Brian Vargus, a political scientist at Indiana University-Purdue. "Nobody paid much attention to it."
Things started to turn when Mourdock supporters challenged Lugar's voter registration and his status on the ballot, noting that Lugar lives in McLean, Va., and sold the Indiana home where he was registered soon after his first election nearly 36 years ago.
"Mourdock went on and on at the registration thing," Vargus said. "He played on the out-of-touch thing."
Lugar was breifly ruled ineligible to vote in Indiana, and had to re-register at the farm his family owns in Marion County to get back on the voter rolls. He was never tossed off the ballot because Indiana allows members of Congress to live out of state and maintain residency.
In fact, in all of the challenges of his residency, Lugar was vindicated. But each time the issue came up, it reminded voters that Lugar, 80, is also a Virginian and a consummate creature of Washington.
Lugar distanced himself from his more international stances and put out a slew of right-leaning domestic policy statements. But little of it affected the attacks of Mourdock and outside groups.
"[Mourdock] just kept at it," Vargus said. "As this went on, Lugar stayed in Washington. His campaign seemed to be very inept. It did not seem to make the case for him, so much as attack Mourdock."
Lugar, the iconic Republican statesman, was reduced to attack dog, and it didn't seem to help much.
"The underlying theme was that he'd been in Washington for more than 30 years, that he was out of touch," said Vargus, noting that Mourdock ads end with, "It's time."
One Tea Party group, the Tea Party Express, is so confident Mourdock will win, it decided to end a 10-day national bus tour by partying with him. "We will be joining State Treasurer Richard Mourdock [Tuesday] night in Indiana celebrating a key Tea Party victory in 2012," the group's chairman, Amy Kremer, said in a statement Monday. "This is going to be an historic year and will start with a major upset when the Tea Party defeats Sen. Lugar."
Still, Mourdock has raised relatively little money -- about $2 million, with more in debt than cash in the bank, according to the most recent federal data -- and has had to depend on outside groups, including the National Rifle Association, the Club for Growth and the Tea Party allied FreedomWorks, which poured millions into the race.
"If he wins, it's not going to be by running a stellar campaign," said Jennifer Duffy, who analyzes Senate contests at the influential Cook Political Report. "The credit has to be divided into two. Tea Party groups, the Club especially, gets 50 percent of the credit. Lugar gets the other 50 percent because he has not run the campaign he needed to run."
The situation leaves Democrats more excited than usual about a race in the Hoosier State.
"Donnelly does have a much better chance against Mourdock," said Vargus, arguing that while the Tea Party can dominate the GOP, it's a different matter in the broader electorate.
"There is a lot of anti-Tea Party sentiment in Indiana," said Vargus, explaining that it's driven by what many voters see as anti-union and anti-education spending pushes by the right. Mourdock and the Tea Party also opposed the auto bailout, which was popular in Indiana. And many voters are angry in general at government -- which in Indiana has a Republican face.
"There's a feeling that there's enough irritation with leadership that Democrats have a chance," he said. Even if Lugar wins, both he and Duffy said they think the senator's residency issues will linger. But still, Mourdock offers the best opening for Donnelly.
For one thing, Mourdock would likely have to depend on the outside groups for funding, and the groups that have been sitting on the sidelines waiting to see if Donnelly has a chance would likely flood into the contest. Among them are business interests that were alarmed last summer when Tea Party intransigence over raising the nation's debt limit nearly led it to default.
Over the weekend, Mourdock went so far as to declare he's opposed to bipartisanship.
"That attitude is not especially helpful to the business community," Duffy said. "They're not especially enthusiastic about having more members who don't want to compromise. So it would not surprise me if the smart business money went with Donnelly."
A GOP operative who did not want to talk on the record because the race had not yet been called, was already looking for a silver lining, pointing out that Mourdock got more votes in his treasurer race in 2010 than Dan Coats, who won the Senate contest that year against conservative Democrat Brad Ellsworth.
"National Republicans firmly believe that whether its Mourdock or Lugar, they will hold this seat," the operative said.
Among the reasons cited were the fact that Democrats have only won three of the last 22 statewide races in Indiana, and that there haven't been any Democrats -- other than father and son senators, Birch and Evan Bayh -- elected to the Senate there since 1970. And, although Donnelly is conservative, he voted like Ellsworth in supporting the health reform law and the economic stimulus -- two issues that were deadly in 2010.
While Purdue's Vargus said he thinks the environment is much different from 2010, he did agree that Mourdock would have the edge.
"I think the conventional wisdom would be it still would be a stretch [for Donnelly]," Vargus said. But not an unimaginable one.
Michael McAuliff covers politics and Congress for The Huffington Post. Talk to him on Facebook.
Below, more Tea Party Senate candidates:
