(Mel Evans/AP)

Yet, one by one, all those assumptions have slowly evaporated in the past year. Congress, we know about. Nothing there. And now the states are steadily backing away, too. On Friday, Chris Christie announced that he would yank New Jersey out of the Regional Greenhouse Gas Initiative (RGGI), a modest cap-and-trade program for electric utilities in the Northeast. Christie’s reasons for doing so weren’t particularly coherent: He called the program a crippling energy tax, but he also noted that, thanks to the recession, permit prices had fallen so low (to about $2 a ton) that the program wasn’t stringent enough to change utility behavior. Got that? It’s a tax, but not a big enough one, so it should be scrapped. Either way, it’s a big blow to RGGI, which was originally intended as a small backbone for a bigger carbon-capping program in the future.

We’re seeing state-level climate programs crumble elsewhere, too. Arizona’s Republican governor, Jan Brewer, pulled out of the Western Climate Initiative, which had been studying a regional cap-and-trade program for various Western states, while Jon Huntsman’s successor in Utah has stopped showing up to meetings. There’s always been a free-rider problem inherent in these voluntary state programs, but nowadays there’s also a partisan hurdle. Republican governors and legislators are outright hostile to anything that so much as smells like climate policy. The once-notable exceptions are now either begging for forgiveness — like Tim Pawlenty — or total outcasts, like Arnold Schwarzenegger and Charlie Crist.

Note that there aren’t many structural factors that can alter this dynamic at the moment. Look at New Jersey. Environmentalism isn’t particularly unpopular there. The state is home to some of the country’s most forward-looking utilities. The largest, PSEG, strongly supported the regional cap-and-trade program and has been experimenting with some innovative efficiency programs. In theory, there should have been plenty of internal pressure on Christie to stay in RGGI. But, like many ambitious governors, Christie has an eye on the national stage, and it’s hard to be a prominent Republican these days and give cap-and-trade a hug. (Note that Mitt Romney bolted out of RGGI back in 2005, despite ample enthusiasm in his state — presumably, the theory went, because you don’t want to irk Midwestern coal interests if you plan to run for president.)

And as long as this dynamic persists, it’s hard to see how regional programs are ever going to be sustainable. You can’t have a multi-state cap-and-trade program if individual states keep coming and going as they please, with each new election. Right now, California is the only state with a comprehensive climate program — it’s the guinea pig for the rest of the country — and even that is at risk of getting torn apart by infighting among enviros. Maybe California’s carbon-capping program will be so successful — and prove so cheap — that other states will rush to mimic it, and then Congress follows suit. (That’s more or less how we got the Clean Air Act, with California playing lab rat.) But it’s hardly a sure bet.

So at this point, I’m no longer sure what’s going to shift the status quo on climate policy in the United States. Maybe the science will get bleaker and more persuasive? Um, except that’s already happening (the National Research Council just put out a new report drawing on loads of new and alarming research), and no one cares. Heat waves and hurricanes will batter the country and everyone will freak out about our coal emissions? Unlikely — as Dave Roberts has noted, catastrophes often make people more resistant to change, not less. Obama’s EPA will save us? Maybe, but the agency’s treading cautiously these days and it’s looking like it’ll make minor changes at best. Cheap natural gas will automatically displace coal? Natural gas might turn out to be just as big a greenhouse-gas emitter.

Probably the best bet for a big shift in climate/energy policy is for the economy to improve. Plenty of studies have shown that concern about the environment is — understandably — pretty well correlated with the business cycle. It’s hard to care about clean air when you don’t have a job. And, if you believe the experts, unemployment might not get back down to 2007 levels — remember the “Inconvenient Truth” era? — until, oh, 2015 or so. Until that happens, then, Chris Christie offers a pretty good indication of where things are going.

Brad Plumer is an associate editor at The New Republic.