Even so, the payoff to the new rules is huge: up to $90 billion a year in benefits compared with around $10 billion a year of costs in the form of slightly higher electricity prices. This is, as David Roberts of Grist says, a very big deal.

And it’s a deal Republicans very much want to kill.

With everything else that has been going on in U.S. politics recently, the G.O.P.’s radical anti-environmental turn hasn’t gotten the attention it deserves. But something remarkable has happened on this front. Only a few years ago, it seemed possible to be both a Republican in good standing and a serious environmentalist; during the 2008 campaign John McCain warned of the dangers of global warming and proposed a cap-and-trade system for carbon emissions. Today, however, the party line is that we must not only avoid any new environmental regulations but roll back the protection we already have.

And I’m not exaggerating: during the fight over the debt ceiling, Republicans tried to attach riders that, as Time magazine put it, would essentially have blocked the E.P.A. and the Interior Department from doing their jobs.