Lugar's Republican primary opponent State Treasurer Richard Mourdock led reporters to Lugar's former home outside Indianapolis this week.
The incumbent Senator has not lived there since 1977, and has lived in Arlington, Virginia ever since.
Two state attorneys general ruled that Lugar is still elegible to vote in Indiana as long as he remains senator. Even so, experts say Mourdock stands to benefit from the accusation.
"Sometimes when you're starting stuff like this, you're not really expecting to influence undecided voters," says Andy Downs, an assistant professor of political science at IPFW. "You're just riling up your supporters to get more activity and money out of them."
A recent poll done by a pro-lugar "super-PAC" showed the incumbent senator has a 25-percent lead among likely GOP voters with 55-percent choosing Lugar, and 30-percent choosing Mourdock.