Genus: Science Believers
Species: As good as typical Democrats
examples: Arnold the Governator, the eight Republicans who voted for cap and trade in Congress in 2009, Bush promises during the 2000 campaign (more or less)
notes: functionally extinct, unless McCain starts getting mad at fellow Republicans again.
Species: Proactive, but not as proactive as Democrats
example: Chris Christie. Others??
notes: they'll do something, maybe even without having to be forced to do something. But not as much as Democrats, which in turn isn't enough.
Species: Embracing science, rejecting acting on the science
notes: this is the leftist side of the Republican Party mainstream. Might actually do something, very limited, if elected to office.
Species: Incoherent action rejecters.
example: Tim Pawlenty. Plenty of others I'm too lazy to track down. McCain on some days.
notes: results will likely vary if elected to office - they won't do much anything to be helpful, but the resistance they have to sane efforts by others could differ from case to case. Might have something to do with what they "really" believe, although considering that issue is a road to madness.
Other waffler species?
Species: Conspiracy True Believers
notes: I suppose you could try to distinguish between the ignorant and the express conspiracy supporters, but it doesn't work too well. These folks will only do what they're legally bound to do, after they've been sued for failing to do what they're legally bound to do.
So the Republican nomination is a battle between action rejecters and conspiracy true believers. Wonderful.