The news from Beijing this week that the U.S. and China are committing to ambitious goals on climate change is, we think, monumental. No two countries are more important to tackling the problem than the largest carbon emitter over the past two centuries, the U.S., and the largest current emitter, China. While many observers are focusing on the ramifications of the announcement for upcoming international negotiations, we believe that the announcement also has potentially profound domestic effects for both countries. For the U.S., the announcement could have significant implications, both legal and political, for the centerpiece of President Obama's climate policy, proposed rules for electric power plants. For China, the announcement is a signal that economic transformation remains the long-term goal. Both countries will need to overcome significant domestic resistance to achieve their stated goals but in our view the joint announcement strengthens the hands of both the U.S. and Chinese presidents.

The U.S.

The Environmental Protection Agency's (EPA) proposed rules for power plants (called the "Clean Power Plan") would require states to cut emissions from the electricity sector 30 percent by 2030 from 2005 levels. Without the rules, or something like them, the U.S. simply can't meet its 26 to 28 percent pledge announced yesterday in Beijing. But the Clean Power Plan is also Exhibit A in the claim by Congressional Republicans that President Obama is an imperial president, using his executive powers to achieve what Congress won't adopt. Moreover, once finalized, the Clean Power Plan will face a fierce legal attack from energy businesses affected by the rules and from conservative state governments reluctant to implement them. Importantly, though, the president doesn't need Congress to implement his policy. He needs the legislative branch simply to keep its hands off the EPA's work and the courts to defer to his agency's regulatory strategy. Politically, China's commitment to halt its emissions growth by 2030 eliminates one of the major arguments opponents make against U.S. action to cut greenhouse gas emissions: that such cuts will hurt the U.S. economically while China continues to pollute. The Chinese commitment may do even more if the announcement succeeds in spurring real international progress. As the 2016 presidential primaries approach, at least some members of Congress may feel more wary about interfering with U.S. efforts to cut emissions by 2030. Republicans keen on appealing to a broader base than their primary voters may decide that obstruction of EPA action should not be a top political priority. They may also worry about undermining the U.S.-China relationship. And the announcement will surely embolden the president to veto any legislation that curtails EPA authority.