Even Medicare itself — which Sanders wants to expand — has been deeply troubling on this front. Shortly after its enactment, it was widely acknowledged to be a runaway program, as the government could not control the reimbursement rates for providers. While Uncle Sam has gained some leverage over the last 30 years, the industry wields incredible influence in determining how much the government pays it.

This is a very diverse array of policies, but they all exhibit a similar flaw. When the government wishes to accomplish some public purpose that it does not have the means to do itself, it contracts with private parties to accomplish the end. In exchange, the state promises, in effect, to guarantee the private parties a profit from the arrangement. The interest groups gladly accept and then use their public bounties to build a political power base, ensuring that their ends are secured, even if they are not in the public interest.

What Sanders and the left wing of the Democratic party aim to do is to top all these previous endeavors — committing to pour trillions of dollars into the medical-services industry for the sake of public health. They assure us that the government will be able, under such an arrangement, to negotiate a better deal for the taxpayer. But this assurance only demonstrates that they do not understand how our government functions in practice. History has shown that precisely the opposite has happened, again and again. Factions that are blessed by the government come to dominate it, to the detriment of the general welfare.