At the beginning of this election cycle, the Indiana Senate race wasn't viewed widely as a pickup opportunity for Democrats. But with just 49 days to go until the election, it's certainly shaping up as a contest to watch in the larger battle for the Senate majority.

(Michael Conroy/AP)

If that sounds surprising, it's because it should. Indiana is a state with two Republican senators and a popular Republican governor. And both Democrats and Republicans agree that President Obama is less popular there than he was in 2008, when he carried the state by a point over Sen. John McCain (R-Ariz.). This time, no one is talking about a repeat victory.

Yet, Rep. Joe Donnelly (D-Ind.) is in a competitive position for the stretch run of the Senate race. An internal poll conducted for his campaign last week shows him running about even with state Treasurer Richard Mourdock (R) (so have other surveys). The National Republican Senatorial Committee is buying ad time in the state. And Mourdock isn't a flawless nominee.

When Mourdock defeated longtime Sen. Richard Lugar (R) in May, a couple of things happened. One, Democrats got the opponent they wanted. For Democrats, defeating Lugar, who enjoyed strong support among moderates, would have been nearly impossible in November. Not so for the more conservative Mourdock. Two, the intense competition in the primary left Mourdock battered and in need of financial reinforcements.

Enter Donnelly, a blue dog Democrat whose South Bend-based district became more Republican in redistricting, prompting him to consider options beyond the House. National Democrats successfully recruited him away from a tough reelection bid and into the Senate race. So far, he's held his own.

Democrats have sought to cast Mourdock as a hard-line partisan while simultaneously pitching Donnelly as a bipartisan legislator. Mourdock has, on occasion, appeared resistant to compromise in his public statements, making it easier for Democrats to present their case. (A recent Donnelly ad even uses Republican vice presidential nominee Paul Ryan against Mourdock on this front.)

A major reason why a Donnelly victory would be an upset is that hitting Mourdock is only half the battle in Indiana. The other half is more difficult, and involves responding to GOP attacks tying the Democrat to Obama, who is unpopular in the state. A recent ad from the anti-tax group Club For Growth, for example, mentions Donnelly's vote for the federal health care law and the stimulus, two big liabilities, given the partisan tilt of the state.

One policy Donnelly has been using to go on offense is the auto bailout. He released an ad earlier this summer touting his support for the measure -- and, notably, Mourdock's opposition to it.

All the talk about national issues -- bailouts, the stimulus, health care, Obama, etc. -- means the outcome of the race could rest more heavily on larger themes than the candidates themselves.

"The two candidates themselves will not decide this race. The race will be decided by outside spending and outside messaging," said Ed Feingenbaum, a nonpartisan political analyst who authors the Indiana Legislative Insight newsletter.

For now, the ad spending battle (taking into account the candidates and outside groups, since the end of the primary) is roughly even, with the GOP side spending a bit more. As is the case with most races, Republican groups are ultimately expected to spend the most money, and that only adds to Donnelly's challenge.

Mourdock got a boost when Romney stumped with him last month. Ryan also appeared with him on Monday. That's what it comes down to for Mourdock -- linking himself to the national ticket that is expected to do well in Indiana and limiting Donnelly’s crossover appeal with discontented Lugar supporters. (Lugar, for his own part, says he won't be stumping with Mourdock this fall.)

In the end, Republicans will probably have to spend more in Indiana than they had originally anticipated. But the same can be said of Democrats in Connecticut, where the Senate race is looking more competitive than most observers believed it would be. In other words, this kind of thing happens in various places on the map each cycle.

To win, Donnelly has to defy the increasingly Republican tilt of the state and outpace his party's presidential nominee there. These are no small tasks and for that reason Mourdock should still generally be regarded as the favorite. But Donnelly's performance so far has put him in a strong position to compete. And that’s welcome news for Democrats looking to hold their slim majority in November.