In the populist era of the early 20th century, the people’s rage was directed not at political elites or government, as it is today, but at huge private monopolies, the “trusts.” Teddy Roosevelt’s trustbusting campaign helped establish competition as America’s fundamental mechanism for inducing private businesses to serve the public. If today’s populists are equally serious about protecting ordinary people, they should declare a similar war against monopoly in health-care markets.

. . .