The late night talk shows joke about everyone and everything, ‘cept Dem Presidential hopeful Barack Obama.

That’s the observation found at the LAT’s Top of the Ticket blog:

A hilarious new study of late-night political jokes, due to be released later today, finds the network comedians clearly avoiding humor about Democratic candidate Barack Obama, while piling the jokes on President Bush and Sens. John McCain and Hillary Clinton.

The study by the Center for Media and Public Affairs finds that only cable’s Comedy Central — whose primary comedians, Jon Stewart and Stephen Colbert, more closely follow the day’s headlines, which have been dominated by Obama — has slightly more jokes about the freshman Illinois senator.

The study covered all jokes between Jan. 1 and July 31 in late-night monologues by Jay Leno, Conan O’Brien, David Letterman, Stewart and Colbert.

Is anyone surprised? Does anyone still watch those shows?