Apparently the EPA is, for the first time, clearing the way to regulate greenhouse gasses under the Clean Air Act. This has potentially far-reaching implications, particularly with a Democratic president and congress. Cap and trade regulation is bound to be extraordinarily unpopular, and the party that passes it is going to have some 'splaining to do when voters notice higher charges on their electricity and gas bills. But if the EPA concludes that it already has the authority to regulate carbon, all the part in charge has to do is . . . nothing. That won't be popular if energy prices are rising, but it's not nearly as politically tricky as actively making people pay more for energy.