In politics, it seems, fat cats come in all sorts of breeds.

A group called The National Republican Trust aired a hard-hitting ad late last night in Madison, Wis. attacking public sector unions. In one part, the ad featured video of union leaders – including AFL-CIO president Richard Trumka – as a voiceover wonders, “Are these fat cat union bosses trying to destroy our country?”

The use of the term “fat cats” is noteworthy because President Obama has used it to describe those in the private sector who are often at odds with union leaders – Wall Streeters. In December 2009, he told CBS, “I did not run for office to be helping out a bunch of fat cat bankers on Wall Street.”

There were no specific donor disclosures on The National Republican Trust’s website, but the group describes its supporters as coming “from all walks of life,” and sharing “one common belief, that America has been a great nation because of her people and their enduring values.”