Here is the question:
... polluters will defend their right to pollute, but why can they count on Republican support? When and why did the Republican Party become the party of pollution?
The striking fact is that previous Republican presidents (Nixon and George H. W. Bush) played major roles in defending our environment. EPA was established under Nixon and expanded under Bush. Now their party has undergone some transformation making the GOP defenders of pollution - on every issue, always. Just for example:
... Today’s Republican Party is putting a conspiracy theorist who views climate science as a “gigantic hoax” in charge of the Senate’s environment committee. And this isn’t an isolated case. Pollution has become a deeply divisive partisan issue.
What happened? Here is Krugman's take.
The basic story of political polarization over the past few decades is that, as a wealthy minority has pulled away economically from the rest of the country, it has pulled one major party along with it. True, Democrats often cater to the interests of the 1 percent, but Republicans always do. Any policy that benefits lower- and middle-income Americans at the expense of the elite — like health reform, which guarantees insurance to all and pays for that guarantee in part with taxes on higher incomes — will face bitter Republican opposition.
And environmental protection is, in part, a class issue, even if we don’t usually think of it that way. Everyone breathes the same air, so the benefits of pollution control are more or less evenly spread across the population. But ownership of, say, stock in coal companies is concentrated in a few, wealthy hands. Even if the costs of pollution control are passed on in the form of higher prices, the rich are different from you and me. They spend a lot more money, and, therefore, bear a higher share of the costs.
In the case of the new ozone plan, the E.P.A.’s analysis suggests that, for the average American, the benefits would be more than twice the costs. But that doesn’t necessarily matter to the nonaverage American driving one party’s priorities. On ozone, as with almost everything these days, it’s all about inequality.
Krugman considers other possible explanations and finds them incomplete at best. Check out his column.