The Senate health-care legislative draft - officially titled the Better Care Reconciliation Act of 2017 - will, if passed, represent the greatest policy achievement by a Republican Congress in generations.

Given that Democrats have filled the airwaves with wild claims that the bill amounts to mass murder, it may feel jarring to think of the bill as a historic achievement. But it is.

For decades, free-market health-reform advocates have argued that the single best idea for improving U.S. health care is to maximize the number of Americans who can afford to buy health insurance for themselves, in...