The closely contested U.S. Senate race in Indiana is drawing more attention from outside super PACs.
Those groups can raise and spend almost unlimited funds for or against candidates.
In the May primary, outside super PACs spent more on the Indiana Senate race than any other state besides Texas.
And with the Joe Donnelly-Richard Mourdock race rated as a statistical dead heat in the polls, the money is starting to pour in again for the November election, just six weeks away.
Mourdock's campaign is complaining about outside advertising from a super PAC run by Democratic Senate Majority Leader Harry Reid.
But Mourdock, who benefited from a huge advantage in super PAC spending in May in his primary race against Richard Lugar, actually has more of the groups supporting him.
As of now, three major groups -- Karl Rove's American Crossroads, the Koch brothers' Americans for Prosperity and former Indiana Congressman Chris Chocola's Club for Growth -- are spending money on Mourdock.
Two -- Reid's Majority 2012 and the moderate Democratic group Center Forward -- are working for Donnelly.
"To hear Mr. Mourdock complain about ads is almost comical when he has millions and millions and millions and millions and millions being spent on his behalf," said Donnelly. "So this is about the voters of Indiana. If Mr. Mourdock wants to find out what the voters of Indiana are thinking about, he ought to come out. And he ought to talk to voters. And he ought to be able to go to meet and greets and see what they think. That's the best thing."
With only a month and a half to go, the ad blitz is going to mount quickly.
With Mitt Romney trailing President Obama in most of the key states, Washington political strategists believe the big Republican super PACs will start shifting their resources into winning Congress.
And that will make Indiana their main focus.
"I'm afraid so," said Brose McVey, Mourdock’s deputy campaign manager. "This race may determine who runs the U.S. Senate. Mitch McConnell and others have said in recent days that the road to the majority in the U.S. Senate leads through Indiana this year. It's getting more narrow and narrow. And Hoosiers have a chance to really impact the future of this country."
Super PACs spent $2.8 million on the Indiana Senate primary, and they are poised to far exceed that in the fall election.