California is threatening to sue the U.S. EPA for obstructionism.

You’ll recall that the U.S. Supreme Court recently ruled decisively that CO2 is a pollutant under the Clean Air Act, and that implementing restrictions on vehicle CO2 emissions does not abrogate the DOT’s authority to set fuel-efficiency standards. That ruling pretty well destroys the legal basis for the lawsuits automakers have filed against Calif. and other states adopting tough vehicle emissions standards.

Now the only thing standing between California and implementation of its standards is a waiver from the U.S. EPA exempting it from the federal Clean Air Act. The state asked for the waiver way back in 2005, but EPA administrator Stephen Johnson has dragged his feet. So Schwarzenegger just sent him a letter saying he’d sue if Johnson didn’t act within six months.

After intense pressure from Barbara Boxer’s EPW committee, Johnson said he’d have a hearing on May 22 and a public comment period until June 15, but he didn’t say when he’d have an answer. Boxer “said she expected the EPA to make a decision by the middle of the summer and would call agency officials back before her panel after the comment period had closed.” I’m really starting to love this woman.

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Suffice it to say, a lawsuit by California against the U.S. EPA seeking permission to fight global warming would be yet another in a string of public-relations disasters for this executive branch. Couldn’t happen to more deserving bunch.