UPDATED: The Republican presidential debate Wednesday on CNBC became a feast of media criticism.
Sen. Marco Rubio, R-Fla., complained that "the Democrats have the ultimate Super PAC -- it's called the mainstream media."
But the mainstream media aren't what they used to be. The evening newscasts aren't watched with the devotion they were in Walter Cronkite's era or even the long runs of Peter Jennings and Tom Brokaw. Cable news channels have smaller audiences than the evening newscasts. Newspapers are cutting back.
Rubio overstates the power of the "mainstream media." Because of technological advances and the splintering audience, the media have...