It's becoming increasing clear that Tom Friedman was right: the world is flat. In particular, the GOP intellectual world is now 'flat'. Two of their biggest requirements nowadays are the flat tax and the flat earth (temperature). Woe be to the candidate that fails either one.
The flat tax is already virtually a litmus test: just look at what Cain (who started this push), Perry, Gingrich, Bachmann, and even Romney have been saying lately about it. Apparently it's needed because of the alleged tragedy that 47% of people aren’t paying federal income taxes (because they pay other taxes or don't make any money). Four years ago, I would’ve expected them to be ecstatic about that. Ron Paul still is, but I don’t think anybody expects him to win. Instead, the Republican mainstream is firmly in Randian fantasyland, in which we have a few ‘producers’ who could ‘go Galt’ any second now, and the ‘parasites’ (i.e., non-millionaires) should be grateful they’re allowed such luxuries as free oxygen.
The other ‘flat’ litmus test is the flat earth (temperature) caucus — i.e., the only major political party in the world to deny global warming. Who are you going to believe — them or your own lying thermostat? As many have noted, Rick Perry is pushing forcefully for the lead on this one, and got Mitt Romney to follow him… prompting the famous tweet from Huntsman, “I believe in evolution and trust scientists on global warming. Call me crazy.” Sadly, from a near-term political perspective, he is.