Do not ask whether a politician Believes in Global Warming. Ask whether that politician would want their kids to inherit a nice house in South Miami.
(But beware: if this trick gets around, politicians will buy or sell their Florida real estate in order to signal tribal allegiance.)
So by that standard almost no politicians believe in global warming.
Notice how all the rich actors who show up at charity events to "fight global warming" are also lining up to buy beach front property. (They also tend to fly around in private jets, but that's a separate issue.)
Edit: The reason I didn't use politicians in the above example is that not all politicians can afford beachfront property and the ability to do so correlates with other things that may be relevant to whether you want him in power.
-- Mark Friedenbach
Of course, with the prompting to state my own thoughts, I simply had to go and start typing them out. The following contains obvious traces of my own political leanings and philosophy (in short summary: if "Cthulhu only swims left", then I AM CTHULHU... at least until someone explains to me what a Great Old One is doing out of R'lyeh and in West Coast-flavored American politics), but those traces should be taken as evidence of what I believe rather than statements about it.
Because what I was actually trying to talk about, is rationality in politics. Because in fact, while it is hard, while it is spiders, all the normal techniques work on it. There is only one real Cardinal Sin of Attempting to be Rational in Politics, and it is the following argument, stated in generic form that I might capture it from the ether and bury it: "You only believe what you believe for political reasons!" It does not matter if those "reasons" are signaling, privilege, hegemony, or having an invisible devil on your shoulder whispering into your bloody ear: to impugn someone else's epistemology entirely at the meta-level without saying a thing against their object-level claims is anti-epistemology.
Now, on to the ranting! The following are more-or-less a semi-random collection of tips I vomited out for trying to deal with politics rationally. I hope they help. This is a Discussion post because Mark said that might be a good idea.