National Geographic: The U.S. Supreme Court on Monday dealt a blow to an Obama administration regulation cutting mercury and other toxic emissions from power plants. The court ruled that the Environmental Protection Agency didnt do enough to consider the costs of complying. As a result, the EPA will have to reexamine and perhaps alter its rules. But since the regulation went into effect earlier this year, many power plants have already installed equipment reducing mercury, a neurotoxin linked to lower IQs and other...