Earlier today in the Senate, Alaska's Lisa Murkowski was planning to introduce an amendment that would've blocked (at least for a year) the EPA's authority to craft its own carbon regulations—even in the absence of a climate bill. But, in the end, she backed down, and the amendment never came up for a vote.

So what happened? Lisa Jackson and the Alliance of Automobile Manufacturers both sent frantic letters pointing out that Murkowski's bill would prevent the agency from finishing up its new fuel-economy rules for vehicles. And if that happened, the Alliance warned, automakers would have to deal with the dread "patchwork of conflicting state and federal regulations." Not surprisingly, green groups tend to have more success when they have Detroit's lobbying muscle behind them.

P.S. Mind you, today's little episode doesn't mean that Murkowski opposes acting on global warming, necessarily. She's expressed worry about those bark beetles wolfing their way through Alaska's forests. And here she was just the other day arguing that the House climate bill didn't deliver enough "immediate environmental benefits"—apparently on account of all the offsets businesses are allowed to buy in lieu of making reductions. Hard to argue with that.