A basic precept of American democracy is that petitioners before their government receive a full and fair hearing. The ObamaEnvironmental Protection Agency is in urgent need of that remedial civics lesson.

The EPA inspector general's office last week announced it will investigate the agency's February decision to commence a pre-emptive veto of the Pebble Mine project, a jobs-rich proposal to develop America's largest U.S. copper and gold mine in southwest Alaska. EPA Administrator Gina McCarthy says...