The first theory is obviously correct. The second is a bit misleading, and the third strikes me as a bit of a red herring.
This graph tracking Americans' environmental enthusiasm pretty closely traces our economy's recessions and recoveries, so Kilgore's right that all we can do to hope this line comes back up is wait for the economy to get better.
On point two, I'd say that the radicalization of the Republican party is synonymous with its down-sizing. Here's a graph comparing Republican identification in 2001 v. 2009. The Bush years melted the party down to its hardened, hard-right core. Of course self-identified Republicans are less moderate than a decade ago. The moderates have left.
Finally Kilgore makes what in DC is increasing becoming known as a Washington Post Problem. As James Fallows pointed out here during the climate scientists' email scandal, the New York Times treated global warming as a problem, and the Washington Post treated it more like a debate. This is silly. Global warming isn't a debate. (And it's alarming to watch the Washington Post sacrifice its integrity for some editorial hot air.) But does Kilgore really think that reforming the way that newspapers cover global warming will make the country warm to climate change reform?
If Kilgore and other advocates for climate change reform want somebody to work on their framing devices, I'd ask them to focus on the White House. Selling health care reform has been a terrible struggle, and the pay-off there is tangible: millions of Americans with health care, stricter rules for insurance companies, and so on. Cap-and-trade offers no such immediate benefits for most Americans. In fact it's more like, well, insurance. Many Americans buy home insurance to protect our houses against inclement climate. The administration should try to convince Americans that we can afford insurance worth 1% of GDP to protect the country against inclement climate change -- and even benefit economically from a green tech revolution. That would accomplish much more than any editorial guidelines tweaked inside the offices of the Washington Post.