None of this is to say that regulating greenhouse-gas emission under the Clean Air Act is the best way to address global warming. It almost surely isn’t. And even if environmentalists don’t contest the new rule, it is legally vulnerable. Indeed, the Journal’s strongest criticism was that while the U.S. Supreme Court directed the EPA to consider regulating carbon dioxide as a pollutant two year ago, the justices “said nothing that would let the EPA simply decide on its own to apply the law to some unfavored business while giving others a pass.”
Whether not the EPA should be allowed to do that is, in fact, a great question. But the Journal’s attempt to peg the agency’s tailoring rule as some epiphanic admission that limiting carbon emission poses economic challenges is naïve. The EPA is trying to address those challenges, yes—but it acknowledged them a long time ago.