The study notes that, while Letterman has been particularly hard on Romney, all four shows surveyed have focused more on the Republican than on Obama.

But the breakdown is actually more GOP-friendly than in 2008, when the shows told nearly three times as many jokes about Sen. John McCain (R-Ariz.) as about Obama and also told more jokes about Sarah Palin and George W. Bush than about Obama.

That said, Republicans have been fighting a losing battle with entertainment types for a long time now, and it’s unclear that Romney is paying a higher price than his predecessors. Put the caricatures of Romney next to the caricatures of Bush or Palin, and they seem tame by comparison. …

With Romney, though, the jokes have often served to reinforce one of the Obama campaign’s central arguments against him: that he’s an out of touch rich guy. And that probably doesn’t help Romney.