A dozen states filed suit on Friday to stop the Environmental Protection Agency from enacting its "Clean Power Plan," new rules that will put many coal-fired power plants out of business. The filing came the same week the EPA held nation-wide public hearings about the plan—including in Pittsburgh, where thousands of coal workers turned out to register their unhappiness with the Obama administration's intentions.

Coal workers are upset because the White House-ordered regulatory scheme will badly damage the coal industry...