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By Lawrence Hurley
WASHINGTON, June 2 (Reuters) - The fate of President Barack Obama's new regulations for curbing greenhouse gas emissions from existing U.S. power plants likely lies in the hands of a Washington, D.C., appeals court he largely reshaped through a series of key appointments.
The appeals court has 11 active judges, of whom seven were appointed by Democratic presidents and four by Republicans. Four of the Democratic appointments were made by Obama over the past 13 months.
Though there's no guarantee judges vote along party lines, the court's composition makes it more likely the regulations would face sympathetic judges in a likely court challenge.
The U.S. Court of Appeals for the District of Columbia Circuit, often referred to as the country's second most powerful court, hears most major regulatory cases including those made against air pollution rules.
And although losing parties can appeal to the Supreme Court, the high court's nine justices rarely review the D.C. Circuit's findings.
Cases are heard by three-judge panels, though the losing party can ask the full bench to overturn their decision.
The panels are picked randomly and include not just the court's 11 active judges but also six judges who have taken senior status, meaning they can choose to take a lighter workload. Five of the six are Republican appointees but their influence is limited because only the 11 active judges can vote on whether to consider overturning decisions made by three-judge panels.
Announced by the White House on Monday, the proposed rules call for a 30 percent reduction in greenhouse gas emissions from existing power plants, including coal-fired facilities, under the federal Clean Air Act.
Once finalized in 2015, the regulations are likely to face legal challenges from the coal industry, manufacturers, some utilities and conservative-leaning U.S. states. Republicans and Democrats from coal-producing states already have criticized the proposal.
Their legal arguments could focus on whether the government overstepped its authority under the Clean Air Act by, among other things, giving states considerable flexibility over how they achieve the targets. Lawyers could also argue the EPA has not followed the correct process in weighing the scientific justification for the rule.
At the time Obama sought to fill the four vacancies on the court, Republicans objected. Senator Mike Lee of Utah said in a July 2013 congressional hearing that Obama was trying to "stack the deck to his advantage" with an eye on legal challenges to regulations.
Even before Obama's appointments, the court was relatively receptive to the EPA. Under laws that determine how courts weigh regulations, judges are required to give substantial deference to an agency's findings and not substitute their own policy preferences for the government's.
"Normally the agency's views hold sway," said Sean Donahue, a lawyer who has experience challenging EPA rules that environmentalists dislike.
The U.S. Senate confirmed Obama's first nominee, Sri Srinivasan, in May 2013. Republican resistance to further nominees was overcome when Democratic Senate Majority Leader Harry Reid of Nevada made a change to Senate rules in November of 2013. Three more nominees - Robert Wilkins, Nina Pillard and Patricia Millett - were subsequently confirmed by January 2014.
The D.C. Circuit has long been a political football with senators holding up nominations by presidents of the opposing party.
The EPA has a winning record before the appeals court of late. In this calendar year it has won 8 and lost 2 Clean Air Act cases, some brought by environmental groups and some by industry. The vote breakdown varies, with both Republican and Democratic appointees backing the agency in the bulk of cases.
Significantly, the court upheld in April a regulation that would limit emissions of mercury and other hazardous pollutants mainly from coal-fired power plants. The panel was split 2-1, with two Democratic appointees in the majority and a Republican appointee in the minority.
The agency won its most important victory of recent years in June 2012 when a three-judge panel of the appeals court that included a Republican-appointee, Judge David Sentelle, and two Democratic appointees upheld the Obama administration's first wave of greenhouse gas regulations.
In October 2013, the Supreme Court declined to review most of the legal claims industry groups made against those greenhouse gas rules, although it did agree to consider one narrow slice. A ruling in that case is expected before the end of June.
In April, the Supreme Court handed another win to the EPA by reversing an August 2012 appeals court ruling that struck down an air pollution rule that regulates pollution that crosses state lines. The appeals court decision, made before any of Obama's appointments were made, came from a panel that consisted of two Republican appointees in the majority and one Democratic appointee, who dissented
Before this year, the last major Clean Air Act case at the Supreme Court was seven years ago. That was Massachusetts v. EPA, a landmark case in which the justices ruled for the first time that carbon was a pollutant that the EPA could regulate. (Reporting by Lawrence Hurley; Editing by Howard Goller, Amy Stevens and Martin Howell)