The political chatter this morning is all about the new proposal on greenhouse gases that President Obama will unveil on Monday. The impetus is a story by Coral Davenport, of the New York Times, who writes that the Environmental Protection Agency will call upon states to reduce carbon output from power plants by 20 percent.

By itself, the number doesn’t tell as much. Carbon output in the U.S. has fallen substantially in the last few years, thanks to a variety of factors including the recession, cheap natural gas, and new regulations. A 20 percent reduction from the 2013 level would mean a lot more than a 20 percent reduction from the 2005 level, when emissions were higher. But Davenport’s story suggests that the administration has in mind a significant cut in emissions, something that many environmental protection advocates have said they expect.

Davenport's article also says that many states are likely to react to Obama's proposal by using cap-and-trade systems—that is, schemes in which government establishes some kind of overall ceiling on emissions, then allows companies or states to buy and sell the right to pollute at different levels. Obama wouldn't force states to react this way. As the most recent version of Davenport's article makes clear, it would merely give states that option.

This is not surprising. Informed observers, including advocates on both sides of this debate, have long expected the Administration to give states flexibility over exactly how to reduce emissions. Earlier this week, Dan Utech, one of Obama's top advisers on climate issues, told the Wall Street Journal that the EPA proposal is “going to enable states to move forward in a way that works best for them with the energy resources they have.” A well-reported (and widely circulated) May 21 story by Juliet Eiplerin and Steven Mufson of the Washington Post said that Obama's proposal would "spur regional carbon-trading programs on the East and West coasts."

Even so, the return of "cap-and-trade" to the Washington lexicon is sure to set off alarm bells on the right. As Jonathan Chait of New York magazine has pointed out, Obama's effort to regulate power plant emissions hits all the conservative hot-buttons: