Evan Bayh could be Senate Democrats' surprise success story this November. Indiana's best-known Democrat has the potential to win an open, Republican-held seat for his party that wasn't even on their radar until he entered the race in July.

But if Bayh has an Achilles heel, it's the perception that the former senator and governor doesn't have ties in the state anymore. And so far, Bayh isn't doing much to dissuade voters of that perception.

CNN's Manu Raju reports that election officials there listed him as an "inactive" voter because they couldn't confirm he lives in Indianapolis. Bayh is still a registered voter there -- he voted in the primary in May -- but this was the first step in a long, long list of steps to remove inactive voters from the roll. And Politico's Seung Min Kim reports Bayh owns much more property outside Indiana than in it: two $2 million-dollar homes in Washington and a condo in Florida vs. a one-bedroom condo in Indianapolis listed at $59,000.

Bayh isn't the first, nor the last, politician to struggle with having put roots down in Washington. Most recently, Liz Cheney -- the daughter of former vice president Dick Cheney -- had to bat down similar accusations in her Wyoming congressional primary. Or more accurately, she drowned them out. Cheney raised nearly seven times more than her opponents. She won Tuesday.

Bayh himself is trying to shrug this all off by saying that politicians do this all the time. Here's what he told Politico's Kim:

[Former GOP Indiana Sen.] Dick Lugar, when he was in the Senate, Dan Coats right now in the Senate, have all had to juggle representing Indiana while also having a presence in Washington, D.C. There's no difference.

It's true that both Coats, who is retiring, and Lugar, who lost his 2012 primary, had to battle perceptions they, too, were creatures of Washington. Coats was a former high-powered lobbyist when he decided to run for Senate again and had to register to vote in Indiana when he announced his candidacy. He won. In Lugar's 2012 primary, he faced some of the same carpetbagger allegations. He lost.

But since when has "He did it too!" been a good defense in anything? I tried that in elementary school in the playground after I cut in line on the monkey bars; it didn't work.

Bayh really seems to be betting voters won't care. He told Kim it won't be "a compelling issue" for voters this November. And maybe he's right. For any kind of narrative to stick in a campaign, it has to reach a certain level of saturation.

Republicans were already planning to hit Bayh with his out-of-state presence with all the subtlety of a jackhammer. But Bayh, with his $10 million war chest leftover from his decision to retire from the Senate in 2010, had the potential to drown them out, Cheney style.

His campaign says this is an old issue. When Bayh was running for governor in 1988, the Republican incumbent ordered the board of elections to investigate whether Bayh could run for the seat. Bayh sued, won the right to run, and he won. And, he's been running and winning elections ever since.

The two polls we have seen since Bayh got into the race show him leading his opponent,Rep. Todd Young (R), but by varying margins. We put Indiana as the fourth Senate seat most likely to flip parties in November.

But Bayh still has to run a smart race to win. And he did himself no favors by having his voting status questioned a few weeks into the race.