Politico reports on Rick Santorum’s newest television ad: a light-hearted, humorous spot featuring a Mitt Romney double firing mud in vain at a cardboard cutout of Santorum. The ad, which doesn’t rebut any of Romney’s (or his super PAC’s) criticisms, says that Romney’s “negative attack machine” will “backfire” on the former Massachusetts governor. The voiceover also says Romney is “trying to hide from his big-government Romneycare” and his support for “job-killing cap and trade.” Watch the video below: