P.J. O'Rouke's 2004 article on Limbaugh et al:
...the number and popularity of conservative talk shows have grown apace since the Reagan Administration. The effect, as best I can measure it, is nil. In 1988 George Bush won the presidency with 53.4 percent of the popular vote. In 2000 Bush's arguably more conservative son won the presidency with a Supreme Court ruling.
A generation ago there wasn't much conservatism on the airwaves. For the most part it was lonely Bill Buckley moderating Firing Line. But from 1964 to 1980 we went from Barry Goldwater's defeat with 38.5 percent of the popular vote to Ronald Reagan's victory with 50.8 percent of the popular vote. Perhaps there was something efficacious in Buckley'sif he'll pardon the wordmoderation.
I tried watching The O'Reilly Factor. I tried watching Hannity shout about Colmes. I tried listening to conservative talk radio. But my frustration at concurrence would build, mounting from exasperation with like-mindedness to a fury of accord, and I'd hit the OFF button.