Yes.
It is absolutely a condition of the age of the triumph of conservative personality politics, where entertainers shouting slogans are taken seriously as political actors, and where the incentive structures exist to stomp on dissent and nuance, causing experimental voices to retrench and allowing a lot of people to pretend that the world around them is not changing.
To that last point, I believe the opposite is true. I believe the conservative base fully recognizes that the world is changing -- specifically, they recognize the browning of America and "they want their country back." They're not "scared" of healthcare reform or bailouts, they're afraid of no longer being a majority in America. They're afraid of never being able to repeat the glorious whitewash of the 1950s.
Of course the right-wing TV and radio talkers are feeding these people with excuses and dog whistles so they can sleep at night believing that it's not all about the slow fizzle of white conservative America. In addition to the crazy stuff like ACORN, they're being fed with lines suitable for discussion in mixed company -- socially acceptable responses for: "Why are you so scared?"
But here's the problem. As I wrote last night regarding immigration, by freaking out so violently, they're actually making things much, much worse. Which is Ambinder's point.
Adding... One way much of the conservative base is able to fool itself into believing it's not about race is by making it more about advancing "whiteness" rather than the more direct repression of "brownness." They believe this makes their freakout more acceptable -- more about their rights and freedom. It goes without saying, however, that advancing whiteness and repressing brownness are aren't mutually exclusive and are equally about race.
And if you think the white conservative base is screechy and crazy now, just wait until 2050 when white people really will be a minority in America. I'll be 78 years old. Hopefully still blogging about it.