HERE’S WHAT I wanted for Christmas: something that would make us both healthier and richer. And since I was just making a wish, why not ask that Americans get smarter, too?

Surprise: I got my wish, in the form of new Environmental Protection Agency standards on mercury and air toxics for power plants.

These rules are long overdue. We were supposed to start regulating mercury more than 20 years ago. But the rules are finally here and will deliver huge benefits at only modest cost.

So, naturally, Republicans are furious. But before I get to the politics, lets talk about what a good thing the EPA just did.

As far as I can tell, even opponents of environmental regulation admit that mercury is nasty stuff.

Its a potent neurotoxicant: the expression “mad as a hatter” emerged in the 19th century because hat-makers treated fur with mercury compounds, and often suffered nerve and mental damage as a result.

Hat-makers no longer use mercury (and who wears hats these days?), but a lot of mercury gets into the atmosphere from old coal-burning power plants that lack modern pollution controls.

From there, it gets into the water, where microbes turn it into methylmercury, which builds up in fish. And what happens then?

The EPA explains: “Methylmercury exposure is a particular concern for women of childbearing age, unborn babies and young children, because studies have linked high levels of methylmercury to damage to the developing nervous system, which can impair children’s ability to think and learn.”

Sounds like something we should regulate, doesn’t it?

The new rules would also have the effect of reducing fine-particle pollution, which is a known source of many health problems, from asthma to heart attacks.

In fact, the benefits of reduced fine-particle pollution account for most of the quantifiable gains from the new rules. The key word here is “quantifiable”: the EPA’s cost-benefit analysis only considers one benefit of mercury regulation, the reduced loss in future wages for children whose IQs are damaged by eating fish caught by freshwater anglers.

There are without doubt many other benefits to cutting mercury emissions but the agency doesn’t know how to put a dollar figure on those benefits. Even so, the payoff to the new rules is huge: up to $90 billion a year in benefits compared with $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 US politics recently, the GOP’s radical anti-environmental turn hasn’t got 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.

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 EPA and the interior department from doing their jobs.

You may have heard reports to the effect that Jon Huntsman is different. Never mind. He, too, has been assimilated by the anti-environmental Borg, denouncing the EPA’s “regulatory reign of terror” and predicting the new rules will cause blackouts by next summer, which would be a neat trick considering they won’t even have taken effect yet.

More generally, whenever you hear dire predictions about the effects of pollution regulation, you should know that special interests always make such predictions and are always wrong.

Power companies claimed rules on acid rain would disrupt electricity supply and lead to soaring rates; none of that happened, and the acid rain programme is an example of how environmentalism and economic growth can go hand in hand.

But again, never mind: mindless opposition to “job-killing” regulations is now part of what it means to be a Republican. And I have to admit that this puts something of a damper on my mood:

The EPA has just done a very good thing, but if a Republican wins next year's election, he or she will surely try to undo this good work. Still, those who care about the health of their fellow citizens, and especially children, have something to celebrate. – ( New York Times)