And Mourdock won't have much trouble rallying Republicans around him in case of an upset. He's already secured the backing of most county party officials, and notably Republican members of Congress are staying on the sidelines for the primary.
The trajectory of the race
: In Nevada and Delaware, O'Donnell and Angle ran under the radar for much of the primary campaign. By contrast, Mourdock entered the race very early on in the cycle, has already attracted national buzz and, at least up to now, has prevented any other conservative candidates from jumping in that would split the anti-Lugar vote.
His early entrance allowed him to become the symbol of a wider conservative frustration in the Hoosier State over Lugar's recent record -- including his vote for TARP and his work with the Obama administration on foreign policy and backing of the president's Supreme Court nominees.
If Mourdock achieves the tough task of unseating a political icon in Indiana, he will emerge in the general election stronger, not weakened. Angle's victory was due in part to a crowded field and the collapse of onetime GOP frontrunner Sue Lowden
. O'Donnell narrowly won the primary only after being subjected to a barrage of negative media coverage that all-but-doomed her chances in the general election.
The state's electoral climate
: President Obama narrowly carried the state in 2008 - a result that Mourdock credits to Lugar's close relationship with Obama - but it's going to be challenging to repeat that feat again in 2012. The state has suffered through hard economic times, and turned decisively against Democrats in 2010. Sen. Dan Coats
won a contested race handily, and Republicans picked up two House seats. Republicans currently control all offices chosen by statewide ballot. And Indiana Gov. Mitch Daniels
, a potential presidential contender, is still widely popular.
The white, blue-collar demography of the state also makes it more challenging for Obama to win again in 2012 compared to other states with more college-educated, diverse populations. (Our National Journal Democratic insiders just ranked it
as the hardest state for Obama to keep in his column.) All that means that whoever emerges as the Republican nominee in the Senate race would start out as the early favorite.
The Democratic nominee
: While Democrats like the idea of Rep. Joe Donnelly
(D-Ind.) entering the race - a distinct possibility, given that Donnelly's district is likely to become more Republican after redistricting - he has not yet fully committed to running. After Donnelly, there are not many other options, as Democrats have a very thin bench in the state (and it's not exactly like Democrats are rushing to run for statewide offices, as several top names have taken themselves out of the running in recent weeks).
Donnelly is also untested in a statewide race, barely held onto his House seat last year and could face scrutiny over his voting record if he is the nominee.
"If it's a match-up in the fall between Mr. Donnelly and myself, he is in essentially the same position Brad Ellsworth was in last fall, when Ellsworth got crushed," Mourdock said.