The U.S. Court of Appeals for the D.C. Circuit heard oral arguments Sunday in West Virginia v. Environmental Protection Agency, the challenge to President Obama’s signature global warming agenda called the Clean Power Plan.

The challengers did not fare well before the 10 judge panel, where Democrat-appointees hold a 6-judge majority.

CPP sets specific carbon-deduction targets for each state based on the amount of carbon dioxide they emit in the course of generating electricity. The EPA gave the states some flexibility in deciding how to achieve emissions. They could elect to have the power grid bare the lion’s share of reduction responsibilities, or triage the effort by capping power plant emissions and encouraging development of renewables and incentivizing other market-based forms of carbon reduction.

Ultimately, EPA hopes the Plan will cut carbon emissions by nearly a 30 over the next decade, as compared to 2005 levels. The Plan is essential to the Paris climate accord. The U.S.’s agreement to pursue dramatic reductions strengthens the convention’s credibility. Without robust American commitment, the accord’s success elsewhere could wane.

The arguments ran a six hour gauntlet of meandering arcana typical of student government meetings. The hearing was divided into several segments for specific topics — and a lunch break for spent advocates and enterprising members of the judicial press.

Perhaps the most remarkable moment of the marathon slog came when Eric Hostetler, the U.S. Department of Justice lawyer representing the EPA, conceded that nothing in the CPP would prevent the agency from setting a standard of zero carbon emissions for the states. The stunning admission came as three Republican appointees on the panel, Judges Brett Kavanaugh, Janice Rogers Brown, and Thomas Griffith, staged a tripartite probe as to what the EPA’s position portends for separation of powers. Hostetler’s flairs of exasperation, and even anger, made tense the usually decorous courtroom.

Nor did the EPA’s Hostetler escape the scrutiny of Judges Sri Srinivasan and Patricia Millett, both of whom are Obama-appointees to the D.C. Circuit. Though neither signaled they were prepared to side with the court’s GOP appointees, they did participate in extended speculation as to whether Congress had made an explicit delegation of authority to EPA, a key point upon which this case turns.

In that vein, there was also extended discussion of a controlling U.S. Supreme Court precedent relevant in this area. In Utility Air Regulatory Group v. EPA, Justice Antonin Scalia wrote for the Court:

When an agency claims to discover in a long-extant statute an unheralded power to regulate “a significant portion of the American economy,” we typically greet its announcement with a measure of skepticism. We expect Congress to speak clearly if it wishes to assign to an agency decisions of vast “economic and political significance.”

The challengers contend this is in fact an assertion of “unheralded power” with “vast economic and political significance” which Congress did not assign to the agency. The challengers found allies on the court’s right-wing to this extent. Brown quoted a White House press release trumpeting the CPP has a monumental and transformative tool for circumventing Congressional torpor. Kavanaugh suggested the economic impacts would devastate the coal industry. “You’re setting unachievable limits in an effort to drive those (plants) out of business,” he told Hostetler. “Lots of people are going to lose their jobs, lose their livelihoods.”

Others on the panel were more skeptical. “You can’t survive in this market unless you do that,” Judge Judith Rogers, a Clinton appointee, said of the inevitable transition from coal to other forms of energy.

The panel struggled to reconcile UARG with another important precedent in this area, AEC v. Connecticut, wherein a unanimous Supreme Court found electric companies are immune to civil claims concerning greenhouse gas emissions, because emissions management is the exclusive province of the EPA, per section 111(d) of the Clear Air Act. Millett loosed rhetorical barbs on this matter, accusing the energy industry of trying to stage a “bait and switch.” The industry was happy to let the EPA use section 111(d) to protect them from civil litigation, but cried foul the moment the agency attempted to use that authority.

An exhilarating and convincing display of chutzpah came when the court turned to the case’s Administrative Procedure Act issues. Challengers claim that the final version of the CPP is not a “logical outgrowth” of the plan as it existed in the first phase of its promulgation, as the APA requires. EPA responds that the plan changed during the course of the “notice and comment” phase of the APA rule making process. A lawyer for the challengers, Thomas Lorenzen, rooted much of his time at the podium leading the court through an lengthy colloquy on the correct analysis of notice and comment issues, essentially telling the court that handles more APA issues than any other in the country “You’ve been doing this wrong the entire time.”

The panel struggled with the Chevron issues at play. Chevron deference requires court’s to defer to an agency’s interpretation of the law, where the law is ambiguous and their interpretation is reasonable. EPA argues there is ambiguity at play here. Section 111(d) of the Clean Air Act, the section from which EPA claims it has authority to promulgate the CPP, precludes the agency from regulating air pollutants “emitted from a source category,” regulated under Section 112 of the same legislation. Power plants are among the source categories regulated by Section 112. In other words, the provisions are in contradiction with each other, creating an ambiguity. The argument met a receptive audience from members of both ideological camps.

Though the deluge of minutia the court shifted through was wide and deep, all signs point to a 6-4 decision in favor of the EPA, with the possibility of ideological melanges emerging on specific questions.

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