In Massachusetts v. Environmental Protection Agency, a copy of which can be found here, the U.S. Supreme Court ruled in 2007 that greenhouse gases are “pollutants” that may be regulated by the EPA under the Clean Air Act.  As a result, the EPA has been issuing regulatory actions to control greenhouse-gas emissions in the United States, prompting some legislators to voice concern that their economic impacts have not been adequately considered.  Information about those initiatives can be found here. 

It is important not to lose sight of just how significant a component these initiatives are in the disagreement that may lead to a partial shutdown of the U.S. government.  Earlier this week, the House of Representatives voted to restrict regulation of greenhouse gases by the EPA, but the effort was defeated in the Senate.  The fallback plan — to include riders to the spending bill that would block funding for EPA regulations limiting greenhouse-gas emissions — appears also to be failing.  But things continue to change by the minute in these very fluid negotiations.  One thing is certain:  no matter what the specific parameters of a compromise on the spending bill, this debate is not going away.