For the most part, private equity companies don’t contribute equity capital. They do the opposite — loading up the enterprise with debt, paying themselves large fees, cutting jobs and wages and extracting cash, rather than investing in the health of the enterprise. When an operating company is stripped of assets and loaded with debt to the point that it can’t continue, private equity owners then use the bankruptcy code to exit and move on, having already taken exorbitant profits.

Much of the undertow on wages and job security is a result not just of global competition or automation but also of private-equity ownership of some $4.3 trillion worth of operating companies, in sectors that include retailing, hospitals, nursing homes, newspapers, rental housing, private prisons, for-profit child care, payday lenders and private universities, employing well over 10 million workers and affecting millions of others. These, as it turns out, are the industries in which Trump voters often work.

The operating companies, taken into and out of bankruptcy, are household names, like Toys “R” Us, Radio Shack and Albertsons. But the maze of private equity firms, with names like Carlyle, Cerberus and Blackstone, are not.

When Mr. Trump was elected, his story was that the Wall Street influence would be offset by self-proclaimed economic nationalists, such as the chief strategist Stephen Bannon and the trade negotiator Robert Lighthizer. Mr. Bannon had counseled bringing back manufacturing, investing heavily in infrastructure, getting tough with China and taxing the rich. Economic nationalism, Bannon-style, might actually deliver something tangible to Mr. Trump’s base.

Today, Mr. Bannon is long gone from the White House, busy settling scores with Mitch McConnell. Getting tough with China on trade issues has taken a back seat to enlisting Beijing’s cooperation on North Korea. After a blitz of corporate lobbying, Nafta renegotiation drags on. The power struggle at the White House between the nationalists and the globalists from Goldman is being won by the usual suspects.

Why don’t Trump voters get that they are being had? Four basic reasons, I think.

First, there is oft-remarked displacement of pocketbook grievances by cultural resentments. But there are three other, more subtle causes.

For starters, the sources of economic assault on regular people are opaque. Investment banking and private equity are cloaked in obscurity. The health, safety, labor, environmental and financial regulations being gutted are intelligible only to specialists.