Global Warming Goes to Court

The Bush administration has been on a six-year campaign to expand its powers, often beyond what the Constitution allows. So it is odd to hear it claim that it lacks the power to slow global warming by limiting the emission of harmful gases. But that is just what it will argue to the Supreme Court tomorrow, in what may be the most important environmental case in many years.

A group of 12 states, including New York and Massachusetts, is suing the Environmental Protection Agency for failing to properly do its job. These states, backed by environmental groups and scientists, say that the Clean Air Act requires the E.P.A. to impose limits on carbon dioxide and other greenhouse gases emitted by new cars. These gases are a major contributor to the "greenhouse effect" that is dangerously heating up the planet.