Last week, Citizens United, a group supporting Mourdock, released a poll showing the treasurer leading 44 to 49 percent over longtime Senator Dick Lugar.
In response this week, Lugar's campaign has released a series of new ads, including one featuring Governor Mitch Daniels. In the ad, Daniels argues Lugar's experience gives Indiana more influence in Washington politics.
But the Lugar campaign did suffer an advertising setback this past week. On Thursday the American Action Network which supported Lugar announced it would drop its efforts and "let race play out."