Humor versus Seriousness as Political Persuasion

I've been thinking about liberal and conservative "public voices." It strikes me that some of the most well-known liberal voices in American today are comedians or people known for being funny. Like the fabulous Jon Stewart of the Daily Show (see the link to the left) or Al Franken of SNL and Air America (http://www.ofrankenfactor.com). Al Franken even has a new book coming out called The Truth (With Jokes).

Now the equally prominent voices on the right are not nearly as funny. They are serious guys like Rush Limbaugh and Pat Robertson (I'm not going to put links to their sites on MY blog--they get plenty of links elsewhere). Robertson would never write a book called The Truth (With Jokes); he'd be more likely to write something like The Truth (With Sermons).

So why is it that humor is the favored mode of communication among liberal public voices and sternness is the tone of most conservatives? Why has each side turned to such different means of persuasion? I guess the fact that right now the US is pretty evenly made up of liberals and conservatives proves that neither side has a lock on persuasion. Of course good political humor is serious commentary, so I think the dudes on the left have it all right, but why does the stone cold rhetoric of the conservatives work on so many of my fellow Americans?

I haven't yet mentioned the fact that these prominent public voices are all straight (I presume) white guys, but that is a subject for another blog . . .