One economic option not given much weight in the final rule, however, is a carbon tax. McCarthy said that the EPA preferred to keep the suite of options to the "standard ways "¦ the utility world does business."
The regulation is expected to face an onslaught of litigation and has already been subject to an unprecedented legal challenge before it was even finalized, a lawsuit that was thrown out by a panel of judges in June. Lawyers for the oil-and-gas industry and the environmental movement have been gearing up to attack and defend the regulation, and a legal battle over the rule is likely to drag on for years. But McCarthy was quick to say that the rule is legally sound, cautioning that Americans will hear "the same tired plays from the special-interest playbook," and adding simply that "they are wrong."
Purple state senators facing tough 2016 elections
Vulnerable senators on both sides of the aisle staring down tough elections will face pressure to take a stand on the regulation. New Hampshire's Kelly Ayotte has expressed concern about climate change, and environmentalists will be quick to pressure her for a position on the rule. Ayotte did not join 41 Senate Republicans in sending a letter to the president asking for the administration to take the rule off the table. If Ayotte decides to support the rule, she could win environmental support during her 2016 reelection race but would expose herself from attack on the Right. Illinois's Mark Kirk, meanwhile, has faced constant criticism from the Left over his lack of support for the regulation in what is expected to be a tight 2016 race.
Democrats won't be immune either. Michael Bennet faces a tough race in Colorado and will likely face questions from his state's fossil-fuel industry over the expected impact.
Natural gas was expected to win a major boost under the draft rule, but that treatment appears to have changed in the final version. States can still cut climate pollution by switching from coal generation to natural gas, a move that environmentalists are wary of, given that America's fracking boom has driven down the cost of natural gas. But while the proposed rule predicted a quick ramp up in the use of natural gas, the final rule projects that natural-gas power generation will be virtually identical to a business-as-usual scenario. That's in large part because of additional incentives for zero-emission sources such as wind, solar, and nuclear.
McCarthy noted that the final rule may result in "less immediate investment in new natural gas, but it certainly hasn't done anything to eliminate or reduce the importance of natural gas in the energy system."
The coal industry
Coal has struggled to compete with natural gas for years. But the release of Obama's climate rule is expected to accelerate that decline, and is likely to trigger even more coal-plant shutdowns — as well as complaints from congressional and 2016 Republicans about an Obama "war on coal."