As the U.S. Court of Appeals for the District of Columbia Circuit weighs whether to block U.S. EPA's proposed carbon limits for existing power plants, the legal tug of war is taking a road trip to Capitol Hill.

West Virginia Republican Sen. Shelley Moore Capito, chairwoman of the Senate Environment and Public Works Committee's clean air subpanel, will head a hearing this week on the legal issues surrounding the so-called Clean Power Plan.

Capito ran for the Senate promising to fight the Obama administration's agenda affecting coal, and she secured a list of key committee assignments to make her case (E&E Daily, March 26).

In March, she helped host a hearing in West Virginia, where she blasted several administration actions, including new power plant mercury standards and climate proposals.

And this week, she'll be questioning formidable figures on both sides of the debate over EPA's Clean Power Plan, particularly concerning its legal underpinnings.

West Virginia Attorney General Patrick Morrisey (R), who is scheduled to testify, also ran on an anti-EPA platform and has become a national leader on fighting the administration's climate actions since taking office in 2013.

Last month, Morrisey was a key figure in Washington, D.C., when the appeals court heard oral arguments on the rule. Oklahoma Attorney General Scott Pruitt (R), also testifying, is an ally in the litigation.

Although EPA has yet to finalize the rule, critics say states are already having to prepare for it, making it ripe for litigation. Plus, say critics, the agency is proceeding on shaky legal foundation (Greenwire, April 16).

Also on tap for the hearing is Sidley Austin LLP attorney Roger Martella, a former EPA general counsel who has expressed strong doubts about the agency's proposed rule surviving court scrutiny, whether now or after it is finalized.

On the other side of the argument will be Kelly Speakes-Backman, chairwoman of the Maryland Public Service Commission, appointed by former Gov. Martin O'Malley (D), who has said her state is well positioned to comply with the proposal.

Georgetown University Law Center professor Lisa Heinzerling will likely be the most forceful voice in the Clean Power Plan's defense. Formerly with the administration, she's considered an architect of EPA's climate agenda.

Schedule: The hearing is Tuesday, May 5, at 10 a.m. in 406 Dirksen.

Witnesses: Patrick Morrisey, West Virginia attorney general; Scott Pruitt, Oklahoma attorney general; Roger Martella, Sidley Austin LLP partner; Kelly Speakes-Backman, Maryland Public Service Commission chairwoman; and Lisa Heinzerling, Georgetown University Law Center professor.