President Obama grabbed headlines this week for (supposedly) bypassing Congress to advance his global warming agenda. As part of what aides characterize as a “muscular and unilateral campaign” to reduce greenhouse gases, the President directed his Environmental Protection Agency (EPA) and his Department of Transportation (DOT) to tighten fuel-efficiency standards for heavy-duty trucks.

Environmentalists swooned, of course, and the media dutifully carried the message far and wide that Obama will do whatever it takes to defeat carbon dioxide, Congress be damned.

Well, not quite.

The truth is that the EPA and the DOT already announced back in August 2011 their intent to issue more stringent greenhouse gas standards for 2018 and beyond—the very same years cited by the President. Stricter rules for model years 2014 to 2018 have already been imposed by the agencies (at a cost of $8 billion).

And neither the President’s pen nor his phone empowered them to act. The real authority resides not in the Oval Office but rather in 42 U.S. Code § 7521—Emission Standards for New Motor Vehicles or New Motor Vehicle Engines, compliments of the Clean Air Act.

For better or worse, the EPA administrator is obligated by law to prescribe “standards applicable to the emission of any air pollutant from any class or classes of new motor vehicles or new motor vehicle engines, which in his judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.”

That’s not to say that this President isn’t well-practiced in unilateral action—abusive, unlawful, or otherwise, as Heritage scholars Elizabeth Slattery and Andrew Kloster have documented. But it’s simply bad form, embarrassing even, that he’s claiming credit for rather routine actions set in motion by Congress passing the Clean Air Act of 1970—when he was in grade school.