We’ve heard a great deal this campaign year about the plight of the working class. The left tells a story about the middle class being destroyed by predatory millionaires and billionaires who are soaking up 99 percent of the “income gains.”

Donald Trump tells a different story. The jobs that once provided a stable middle-class income have been outsourced. If people are unemployed, it’s because the factories are all in Guangzhou or Juarez. Trump promises that he will bring those jobs back.

Of course, neither Trump nor anyone else can bring those manufacturing jobs back, because they weren’t lost primarily to foreign competition. Manufacturing jobs (as opposed to manufacturing outputs, which continue to rise) have been in steep decline since 1947, mostly due to automation and efficiency. Service jobs have been increasing.

You would imagine that if people were unemployed because the 1 percenters have hoarded all the wealth, or because foreigners have absconded with all the factories, the unemployed would express a desire to work. Yet a report from the president’s Council of Economic Advisors finds that only 16 percent of prime age (25-54) men who were not in the labor force in 2015 said they would like to be working. Many are living off relatives and disability payments.

Most adults are in the labor force (88 percent of men and 75 percent of women). But particularly for men, the labor force participation rate has been declining steadily. It was close to 98 percent in 1955.

These findings follow other scholarly work such as that by Princeton economists Angus Deaton and Anne Case, who published a paper last fall showing that death rates among white, middle-aged Americans with high school educations have increased over the past 15 years, while the death rates for other ethnic groups have declined. Alcohol and drug poisoning lead the causes.

What the CEA does not grapple with is the fact that while men’s employment rates and wages have been declining, women’s have been increasing. Women’s labor force participation rates have declined since 2001, but not nearly as much as men’s. As David Autor and Melanie Wasserman of MIT have shown, except for high school dropouts, women at every level of education have seen their wages rise since 1979. But men in every category except college graduates have lost ground.

It’s likely that the decline in brawny jobs, due to their automation, has hurt men more than women. But these trends have been very long term and don’t explain why men have not been as adept as women in adjusting to changes in the jobs landscape.

Authors of the report “Wayward Sons” have looked beyond the usual explanations (de-unionization, globalization, automation, immigration) for what ails American men and examined the biggest change of the past 50 years — family life. While growing up in single-parent homes handicaps both girls and boys, it’s more devastating for boys. They lag in school, are less ambitious, and are less likely to be gainfully employed when they reach adulthood. A significant number also commit crimes and wind up in prison.

With more young men failing to thrive, the pool of marriageable men for young women to consider thus becomes smaller, and the pattern of women raising children without fathers is repeated in a pernicious spiral.