A Democratic super PAC will begin running TV ads later this week in support of Evan Bayh, the party’s nominee for Senate in Indiana, who Democrats fear is being heavily outspent in a suddenly tightening race. 

The expenditures are the first from Senate Majority PAC in the Hoosier State race, which pits Bayh, a former senator, against Republican nominee Rep. Todd Young. 

Shripal Shah, a spokesman for the group, declined to say how much the super PAC would spend in the state, or for how long it would run the ads. But he did say the ads were in response to a deluge of spending from Republican outside groups.

“We’re taking nothing for granted as we work to win back the Senate this November,” Shah said. “Republicans have spent millions — including nearly $5 million in just the last month — on misleading attacks to prop up Todd Young’s struggling campaign. We’re not going to let those attacks go unanswered.”

[GOP Senate PAC Spending $4 Million Against Bayh]

In the last five weeks, one source tracking ad buys in Indiana found that Republicans outspent Democrats by a nearly 2-to-1 margin, $4.9 million to $2.7 million, thanks in large part to sizable investments from GOP-aligned outside groups like the Chamber of Commerce and the Senate Leadership Fund. 

Democrats consider the Indiana race a key part of their plan to take control of the Senate next year, confident that Bayh’s name recognition and longstanding goodwill will let the party win an open-seat race even in a red state. 

But Republicans say questions about Bayh’s post-Senate residency and career let them make a strong case to voters that the longtime elected official isn’t the same man he was when he left office in 2010.

It’s an argument, in fact, they say is working, pointing to a recent WTHR/Howey Politics poll that found Bayh leading by only 4 points, 44 percent to 40 percent.