"Senator Mitch McConnell of Kentucky has begun an aggressive campaign to block President Obama’s climate change agenda in statehouses and courtrooms across the country, arenas far beyond Mr. McConnell’s official reach and authority. The campaign of Mr. McConnell, the Senate majority leader, is aimed at stopping a set of Environmental Protection Agency regulations requiring states to reduce carbon pollution from coal-fired power plants, the nation’s largest source of greenhouse gas emissions... Mr. McConnell’s Senate staff, led by his longtime senior energy adviser, Neil Chatterjee, is coordinating with lawyers and lobbying firms to try to ensure that the state plans are tangled up in legal delays...To make his case, Mr. McConnell is also relying on a network of powerful allies with national influence and roots in Kentucky or the coal industry. Within that network is Laurence H. Tribe, a highly regarded scholar of constitutional law at Harvard Law School and a former mentor of Mr. Obama’s. Mr. Tribe caught Mr. McConnell’s attention last winter when he was retained to write a legal brief for Peabody Energy, the nation’s largest coal producer, in a lawsuit against the climate rules."