The Lorax on the Appalachian Trail

The Supreme Court sizes up a 2,200-mile barrier to development.

To environmentalists, this must look like the perfect legal loophole. Congress gave federal agencies the power to authorize pipelines under the lands they control. But that law excludes “lands in the National Park System.” Who administers the Appalachian Trail? Bingo: the National Park Service.

Ergo, the greens assert, no agency may permit a pipeline to cross the trail, which runs 2,200 miles from Maine to Georgia. That would turn the footpath into a wall to development, since most of the...