Alfred Lotka (1926) gave some math for why living organizations oscillate. In plain words without the squiggles, oscillatory systems have exploratory properties but, at the same time, tend to be more stable then linear ones.

Cultures oscillate?

Probably. And this is a good time in America for wide ranges of opinion.

WSB, 750 AM, Atlanta...Neal Boortz and, many times, Chris Krok (sp?)
WGY, 810 AM, Albany ... Mike Savage, Rollye James (this gal can find conspiracy in a roll of Tums! and she reasons like a guy!)
SRN (Salem Radio Network): Bill Bennett (Morning in America, Mike Medved, Hugh Hewett, and, your hero, Dennis Miller)
CNN radio network: Glenn Beck...should be everyone's hero for his series on Muslim terrorist activities
Laura Ingraham...can be great when she's pissed...chatty & silly when not.
Ann Coulter...I love the obnoxious bitch!

And of course, the pioneers, Bob Grant (WABC 770 AM, NYC) and Rush Limbaugh (everywhere!)

Omigod! I did that from memory!

Essential tool: a good AM receiver. Recommend CC Radio.com. They make a jewel for about $170 and have a new version that includes a SW band. If you really want to be old fashioned, then catch these folks on the Web.

Also in regard to evolution: the "right" seems exclusive to auditory channels while the left dominates the visual input...not sure why, might be a product of contingency, might also be one of neurology.

JimB