New Republic: The Supreme Court agreed on Tuesday to review an Environmental Protection Agency regulation limiting how much mercury, arsenic, and other pollutants coal-fired power plants can emit. The case is clearly important because of the health benefits--humans exposed to mercury are at risk for a host of health conditions--but there is another issue at stake. The rule, known as the Mercury and Air Toxics Standard, (MATS) will help determine how many coal plants retire over the next few years, making it a...