The "quiet catastrophe" is particularly dismaying because it is so quiet, without social turmoil or even debate.

It is this: After 88 consecutive months of the economic expansion that began in June 2009, a smaller percentage of American males in the prime working years (ages 25 to 54) are working than were working near the end of the Great Depression in 1940, when the unemployment rate was above 14 percent.

If the labor-force participation rate were as high today as it was as recently as 2000, nearly 10 million more Americans would have jobs.

The work rate for adult men has plunged 13 percentage points in a half-century. This "work deficit" of "Great Depression-scale underutilization" of male potential workers is the subject of Nicholas Eberstadt's new monograph "Men Without Work: America's Invisible Crisis," which explores the economic and moral causes and consequences of this:

Since 1948, the proportion of men 20 and older without paid work has more than doubled, to almost 32 percent. This "eerie and radical transformation" - men creating an "alternative lifestyle to the age-old male quest for a paying job" - is largely voluntary. Men who have chosen to not seek work are two-and-a-half times more numerous than men who government statistics count as unemployed because they are seeking jobs.

What Eberstadt calls a "normative sea change" has made it a "viable option" for "sturdy men," who are neither working nor looking for work, to choose "to sit on the economic sidelines, living off the toil or bounty of others." Only about 15 percent of men ages 25 to 54 who worked not at all in 2014 said they were unemployed because they could not find work.

For 50 years, the number of men in that age cohort who are neither working nor looking for work has grown nearly four times faster than the number who are working or seeking work. And the pace of this has been "almost totally uninfluenced by the business cycle." The "economically inactive" have eclipsed the unemployed, as government statistics measure them, as "the main category of men without jobs." Those statistics were created before government policy and social attitudes made it possible to be economically inactive.

Eberstadt does not say that government assistance causes this, but obviously it finances it. To some extent, however, this is a distinction without a difference. In a 2012 monograph, Eberstadt noted that in 1960 there were 134 workers for every one officially certified as disabled; by 2010, there were just over 16. Between January 2010 and December 2011, while the economy produced 1.73 million non-farm jobs, almost half as many workers became disability recipients. This, even though work is less stressful and the workplace is safer than ever.

Largely because of government benefits and support by other family members, nonworking men ages 25 to 54 have household expenditures a third higher than the average of people in the bottom income quintile. Hence, Eberstadt says, they "appear to be better off than tens of millions of other Americans today, including the millions of single mothers who are either working or seeking work."

The U.S. economy is not less robust, and its welfare provisions not more generous, than those of the 22 other affluent nations of the Organization for Economic Co-operation and Development. Yet the United States ranks 22nd, ahead of only Italy, in 25-to-54 male labor-force participation. Eberstadt calls this "unwelcome 'American Exceptionalism.' "

In 1965, even high school dropouts were more likely to be in the workforce than are the 25-to-54 males today. And, Eberstadt notes, "the collapse of work for modern America's men happened despite considerable upgrades in educational attainment." The collapse has coincided with a retreat from marriage ("the proportion of never-married men was over three times higher in 2015 than 1965"), which suggests a broader infantilization. As does the use to which the voluntarily idle put their time - for example, watching TV and movies 5.5 hours daily, two hours more than men who are counted as unemployed because they are seeking work.

Eberstadt, noting that the 1996 welfare reform "brought millions of single mothers off welfare and into the workforce," suggests that policy innovations that alter incentives can reverse the "social emasculation" of millions of idle men. Perhaps. Reversing social regression is more difficult than causing it. One manifestation of regression, Donald Trump, is perhaps perverse evidence that some of his army of angry men are at least healthily unhappy about the loss of meaning, self-esteem and masculinity that is a consequence of chosen and protracted idleness.