THE UNITED STATES has more doctors now than ever before. There were nearly seven hundred thousand doctors in active practice in 1999, twice as many as in 1970 and ten times more than in 1940. Yet for 50 million Americans, a trip to the doctor requires a long-distance commute. These Americans live in rural areas where the nearest medical services might be fifty or one hundred miles away. Two-thirds of the nation's roughly three thousand counties do not have the doctors they need. Federal guidelines call for there to be a minimum of one doctor for every three-thousand five-hundred people. In 1998 America's rural communities fell short of this standard by nearly five thousand doctors.

In 1996, for example, five Colorado counties had no primary care physicians and many of the state's other counties failed to reach the federal minimum standard. This...