Still, doesn’t something have to be done about Medicare? No — which is my third point. People like Paul Ryan, the speaker of the House, have often managed to bamboozle the media into believing that their efforts to dismantle Medicare and other programs are driven by valid economic concerns. They aren’t.

It has been obvious for a long time that Medicare is actually more efficient than private insurance, mainly because it doesn’t spend large sums on overhead and marketing, and, of course, it needn’t make room for profits.

What’s not widely known is that the cost-saving measures included in the Affordable Care Act, a.k.a. Obamacare, have been remarkably successful in their efforts to “bend the curve” — to rein in the long-term rise in Medicare expenses. In fact, since 2010 Medicare outlays per beneficiary have risen only 1.4 percent a year, less than the inflation rate. This success is one main reason long-term budget projections have dramatically improved.

So why try to destroy this successful program, which is in important respects doing better than ever? The main answer, from the point of view of people like Mr. Ryan, is probably that Medicare is in the cross hairs precisely because of its success: It would be very helpful for opponents of government to do away with a program that clearly demonstrates the power of government to improve people’s lives.

And there’s an additional benefit to the right from Medicare privatization: It would create a lot of opportunities for private profits, earned by diverting dollars that could have been used to provide health care.

In summary, then, privatizing Medicare would betray a central promise of the Trump campaign, would specifically betray the interests of the voter bloc that thought it had found a champion, and would be terrible policy.