The national Democratic Party is dipping its toe into the open Indiana Senate race, sending $250,000 to the state party for an ad on behalf of Rep. Joe Donnelly’s (D-Ind.) campaign.

The investment, while small, signals the Democratic Senatorial Campaign Committee’s desire to make the race competitive now that Sen. Richard Lugar (R-Ind.) has fallen in a primary. Democrats argue that state Treasurer Richard Mourdock is a weak GOP nominee, and they seem intent on testing out that theory with some messaging.

The new ad hits Mourdock for being a “tea party candidate,” saying Social Security is “unconstitutional” and supporting cuts to Medicare. It comes as Donnelly’s campaign has struggled to raise money early in the campaign and could use some presence on the air.

The $250,000 invesment doesn’t match the $620,000 ad buy that the American Crossroads super PAC just went up with in the Hoosier State, but because that ad is coordinated with Donnelly’s campaign, air time isn’t as expensive. (The fact that Crossroads is spending here too suggests they see at least some chance that the seat could be competitive.)

Republicans professed glee that Democrats were spending money on the conservative-leaning state, where they remain confident of their chances of holding Lugar’s seat.

“This is great news,” tweeted Brian Walsh, a spokesman for the National Republican Senatorial Committee. “I’m sure (Democratic Sens. Jon Tester and Claire McCaskill) are pleased to see that natl Dems just thru $250k down the toilet in Indiana.”