Is the EPA M.I.A. On Regulating Vehicle Emissions?

The Environmental Protection Agency, or EPA, is charged with protecting the environment, per their name, no?  That's why I'm totally puzzled why the EPA has failed to comply with the April 2007 Supreme Court directive that the agency determine whether carbon dioxide and greenhouse gas emissions from vehicles pose a danger to public health and whether these emissions should be regulated.  You see, the Supreme Court ruled that the EPA had authority under the Clean Air Act to regulate tailpipe emissions of greenhouse gases.  EPA Administrator Stephen L. Johnson claimed, in an exchange with Senator Dianne Feinstein of California, that he didn't know how many people at the EPA were "directly working on the issue now". 

Why is the Environmental Protection Agency not living up to their namesake?  Does this agency not want to be burdened with the task of regulating vehicle emissions, even if the public health or welfare is endangered?   Perhaps there are more nefarious forces at work here.  The Bush Administration, true to form, has claimed for years that carbon dioxide need not be regulated because it is not identified as a pollutant under the Clean Air Act.  Could it be that George Herbert Walker Bush has influenced the EPA to "stonewall" (as Senator Feinstein accused Stephen L. Johnson of doing) on this issue, hoping that they would somehow be absolved of this great responsibility?  Is the Bush Administration afraid of the potential costs of having to regulate vehicle emissions?  Well, they never seemed to have much issue with dropping billions into other foolish ventures, so there's no need to be Scrooge-esque here, eh?

I'm no scientist, but it is difficult to deny, with tangible evidence like the smog in Los Angeles, that emissions from vehicles have negatively affected the health and welfare of that city's residents to an extreme degree, despite recent efforts to improve the situation by California politicians.  With the driving culture that we have here in the United States, we should be proactive about vehicle emissions so that we don't create more smog-choked urban areas, and one of the keys to moving forward in this venture is to have the EPA leading the charge.  Hopefully they'll stop dragging their feet and quicken their pace to help clean up the air we breathe!