Originally posted at the Think Progress Wonk Room.
In continued defiance of Congressional oversight, the Environmental Protection Agency (EPA) has flatly declined to obey a subpoena from the House Committee on Global Warming and Energy Independence. The subpoena for documents relating to the EPA’s refusal to obey the Supreme Court mandate to regulate greenhouse gases was issued by a unanimous, bipartisan vote on April 2, a year after the Supreme Court decision.
On April 11, the EPA requested and received an
extension to respond, but today the agency has decided not to turn over
the documents: 
Whether or not the EPA has “grave concerns” about “erroneous impressions,” a “chilling effect,” and “institutional prerogatives,” these are not legally defensible reasons to defy a Congressional subpoena. In a terse response, Committee chair Ed Markey (D-MA) found the reasoning “unpersuasive.” The letter continues:
Of course, if the EPA simply turned over the documents, it would no longer be under such a “cloud.”
The EPA is also defying the House Oversight Committee’s subpoena for related documents on White House involvement. Both letters of refusal were written by EPA assistant administrator Christopher P. Bliley—who was OMB head Jim Nussle’s chief of staff in Congress.
Warming Law notes this defiance likely triggers contempt of Congress proceedings for EPA administrator Stephen Johnson.
View the full letter: EPA 4-16-08 Subpoena Response (PDF)