The Supreme Court didn’t just issue a strong rebuke to the Obama administration’s environmental agenda last week. In ruling against the Environmental Protection Agency’s “Mercury and Air Toxics Standards” regulation — commonly known as MATS — the justices showed the danger of complying with a federal regulation before its future has been decided in court. This is an important lesson for states as the administration prepares to finalize its “Clean Power Plan” — a rule that could be significantly more costly than the one before the Court last week.
The court’s ruling in Michigan v. EPA came over three years after the EPA first proposed the MATS rule. The regulation, which went into effect in April of this year, sought to cut by 75 percent the amount of mercury, arsenic, and other emissions from coal- and oil-fired power plants. As of January 2015, it had already turned out the lights on nearly 61,000 megawatts — enough to power 15.5 million homes — of coal-powered electricity generation.