Mother Jones: Coal is America’s cheapest and most plentiful energy source. But in California, coal is a small, shrinking part of the energy picture, and the industry is usually a minor player in state politics. So why are out-of-state coal companies suddenly trying to sink California’s groundbreaking climate change law? The first law of its kind in the nation, California’s Assembly Bill 32 is intended to reduce the state’s greenhouse gas emissions 15 percent by 2020 through a variety of means, …