Over the last few decades we've seen just about every radical conservative idea be completely mainstreamed into our politics and discourse, while at the same time the Noble Defenders of the Left Flank like Joe Lieberman Weekly and Joe Klein have valiantly fought to ensure that every political idea or thought to their left on the rough political spectrum is declared to be "extremist." It's marginalization rhetoric which paints those who those who have those ideas as not just wrong, but actually ineligible to have a seat at the debate table.
And this is how we've gotten to where we are. The Elite Consensus in Washington is that acceptable political thought runs from the New Republic to the Free Republic. Or, as John Harris put it:
I sometimes think that if Washington political reporters ran the government their ideal would be to have a blue ribbon commission go into seclusion at Andrews Air Force base for a week and solve all problems. It would be chaired by Alan Greenspan and Sam Nunn. David Gergen would be communications director, and the policy staff would come from Brookings and the American Enterprise Institute. They would not come back until they had come up with sober, centrist solutions to the entitlements debate, the Iraq war, and the gay marriage controversy.
As I wrote at the time:
Note that the range of opinions runs from people who occupy what is generally called (rightly or wrongly) the center of political opinion to the extreme right. David Gergen is a Republican. Sam Nunn is a conservative Democrat who likes to run around with Warren Rudman telling people the Social Security is DOOOOMED. Alan Greenspan is an extreme conservatarian freak. Brookings prides itself on itself on straddling the political center and hosts such grand contributors to our current mess as Kenneth Pollack, while AEI is a right wing freak show filled with hackery of epic proportions.
In other words, as I've long said, the acceptable positions in Official Washington range from the New Republic to the Free Republic.