The increasingly competitive Indiana U.S. Senate race will see more national money pouring in. The Majority PAC, a Democratic super 527 group, made a $500,000 TV ad buy on behalf of Democratic nominee Joe Donnelly this week.

On Friday, Americans for Prosperity announced it would begin a $700,000 statewide TV ad buy on behalf of Republican nominee Richard Mourdock.

“Congressman Joe Donnelly’s votes for government-run health care has increased taxes and healthcare costs, takes money from Medicare, and gives bureaucrats the power over important personal health decisions,” stated Chase Downham, Indiana State Director of Americans for Prosperity.

With the meltdown of Missouri Senate Republican nominee Todd Akin after his nutty comments on rape last weekend, the prospects of more national money shifting to the deadlocked Indiana Senate race are likely to increase. Crossroads GPS and the Republican Senatorial Campaign Committee have cancelled millions of dollars of TV ad buys in Missouri, once seen as a critical GOP pickup on its quest for a Senate majority. Akin is challenging U.S. Sen. Claire McCaskill.

Howey Politics Indiana Columnist Mark Souder, the former Republican congressman, sees national Democratic spending for Donnelly “a more likely variable.” But he adds, “Ironically, now they have to spend in Missouri which they had surrendered. Republican money probably needs to come to (GOP nominee Richard) Mourdock, but unless he – not others – makes a new mistake, Donnelly will start to fall and the focus will move to real battleground areas. If Mourdock is in doubt, it means the Senate will be Democratic.”

Barney Keller, spokesman for Club for Growth, which had invested close to $2 million in Mourdock’s candidacy in the primary, explained, “There hasn’t been much advertising in the race yet, so I’d avoid hyperventilating over summer poll numbers because you’ll look silly when Mourdock ends up winning. I would note that the DSCC hasn’t made any ad reservations in Indiana, while they have in places like North Dakota and Nevada. Usually, if the national party thinks a race is competitive, they put their money where their mouth is.”

The buy on Donnelly’s behalf comes after a Market Research Poll conducted on behalf of the Indiana Chamber of Commerce showed Mourdock leading 41- 39 percent. In addition to the 17 percent of respondents who are undecided, three percent support Libertarian candidate Andrew Horning.

Dr. Vern Kennedy of Market Research noted that “16 percent of Indiana voters who say they are completely independent will likely determine the outcome of the Senate race.” Kennedy added, “Mourdock has the advantage in the election because more of the 17 percent of undecided voters on this race identify themselves as Republicans than Democrats,” Kennedy explains. “For instance, among those voters undecided on the U.S. Senate race, 33 percent indicated their support for Pence for governor compared to six percent who support Gregg in that race.”

But the Market Research poll shows that among “completely independent voters,” Donnelly’s fav/unfavs stood at 14/4 percent. In Mourdock’s case, completely independent fav/unfavs stood at 11/24. Those voters might not react too well to comments Mourdock made before a Madison Tea Party group challenging them to find the words Medicare and Social Security in the U.S. Constitution (Evansville Courier & Press). “Nowhere is the word ‘entitlement’ present in the enumerated powers,” Mourdock says in a video captured by Democratic trackers.

Democrats and Republicans were virtually equal in responding undecided, 11 and 12 percent. Independent voters favored Mourdock 21 percent, Donnelly 25 percent, Horning 14 percent, while 41 percent were undecided. It’s those voters who will decide this race.

That kind of data is one reason why Donnelly was campaigning with former senator and governor Evan Bayh this week. Bayh has a long history of attracting independent and Republican voters.

“I think the Democratic base is squarely in Joe Donnelly’s camp, and we need to build on that and reach out to independents and Republicans because not only is that the politically sensible thing to do, it’s the only way we’re going to make progress in Washington,” Bayh said. “The two U.S. Senators who were from the same state but from different parties but had the voting record most alike were Dick Lugar and myself.”

Mourdock won a bitterly contested Republican primary against U.S. Sen. Dick Lugar. In that showdown, Mourdock played to his Tea Party supporters which helped him win a stunning 61-39 percent upset. But in doing so, Mourdock alienated himself from many of the independents he needs to win.

The Market Research Poll has Mourdock’s GOP support at 80 percent, while Democrat support for Donnelly is at 84 percent. Both are fairly typical numbers.

Jeff Brantley of the Indiana Chamber noted that at this point, “Mourdock hasn’t closed the deal.”

But Brantley observed of the Market Research polling, Republican self-ID is up “in all state legislative districts” enough for him to believe that five or six swing districts have since been moved to “leans Republican.” That has Chamber analysts sensing a potential Republican wave developing in Indiana, which could give Mourdock a tailwind. While my Indiana House projections in July had the Republicans picking up 63 seats, a number Brantley wouldn’t quibble with, in a wave environment “there is a path to get to the magic” 67-seat super majority.

As for the nine percent drop off of Republican support in the Chamber poll between gubernatorial nominee Mike Pence (at 50 percent) and Mourdock at 41 percent – very similar to the Rasmussen Reports drop off between presidential nominee Mitt Romney and Mourdock – Brantley notes that the two candidates have “branded themselves differently.” Pence, he said, has stayed positive in his message and has maintained control of that message. Mourdock has branded himself as an ardent Tea Party revolutionary.

“There’s real combat going on in the Senate race,, but not in the governor’s race,” Brantley explained. “Any time you come out of a divisive primary, you’re going to have a harder time.”

The columnist publishes at Find him on Twitter @hwypol.