Palm Springs, Calif. — Some new threat is always trying to nose its way into America’s wilderness areas. Fierce battles have been fought over logging, mining and damming these last vestiges of our wild heritage. Now proposed legislation in Congress would allow bikes in wilderness.

This may not seem like a big deal. But the 1964 Wilderness Act forbids bikes and other forms of “mechanical transport” in federal wilderness areas. To allow in bikes would set a perilous precedent that would encourage further efforts to open up these wild places, threatening the very idea of wilderness that the law expresses: “where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.”

To keep wilderness this way, the law is strict, and there is no ambiguity over its ban on “mechanical transport.” The four agencies that administer the nation’s 109 million acres of wilderness — the National Park Service, Forest Service, Fish and Wildlife Service and Bureau of Land Management — interpret the law to prohibit bikes.

Yet leaders of the pro-bike effort, the Sustainable Trails Coalition, argue that lawmakers in 1964 never intended to exclude mountain bikes. They claim the law’s legislative history “shows that Congress would have wanted to allow bikes in wilderness if mountain bikes had existed or they had thought about them.”