Lawmakers Should Tread Carefully On State Health Exchange

Later this month, state legislators will begin discussions about designing and implementing a health-care exchange. If experience is a guide — and it is — Washington lawmakers should tread very carefully because recent events have shown how perilous such efforts can be.

State health-care exchanges, authorized under the federal health-reform law, were originally characterized as virtual open-air markets where health-insurance providers would compete side-by-side so consumers could easily compare coverage and cost. Some states are using the exchanges to introduce single-payer systems, squeezing...