Democrats were apparently expecting that nobody would successfully file for the Senate seat, given the fact that Bayh dropped out a day before the petitions were due. Under Indiana law, the state Democratic Party's central committee has the authority to name a new candidate. If d'Ippolito is indeed able to make the ballot, then the Dems would have to find some other means to get a different candidate -- or else have her as their nominee.
D'Ippolito said the people of Indiana should choose the candidate, not a party committee. "And this is what the machine in Indiana does not want to happen, because they want to choose the candidate, they want to put another Blue Dog in there," she said. "It's a different body than Evan Bayh, same thing, different face, Blue Dog. We don't want any more Blue Dogs. It's bye-bye Bayh, and bye-bye Blue Dogs in the state of Indiana."
I asked d'Ippolito about the possibility that Republicans may have given her a hand. Erick Erickson, for example, personally encouraged his Indiana readers to sign her petitions. "God bless him, because anybody can sign the petition," said d'Ippolitio. "Republican, Democrat, independent, teabag person, any registered voter with a warm pulse can sign."
D'Ippolito was not specifically aware of Republicans who signed her petitions in order to cause problems for the Democrats, but she didn't have a problem with it: "I have no way to know that for sure, but I'm sure that is happening. It's common sense, I think that would be realistic."
Late Update: After telling TPM that she already had the necessary signatures collected, d'Ippolito is now denying to Greg Sargent that she has them yet, saying instead that she would have them in time.