The story I prefer begins with the economy. For much of the 20th century, men without any college education could expect to earn a middle-class salary in fields such as manufacturing and mining. In the 1970s, the share of the labor force working in these brawny industries declined. But men—especially in poor areas where college attainment is low and may even be falling—have struggled to adapt.

The sociologist Kathryn Edin has written that men without college degrees in deindustrialized America have been adrift for decades. They face the simultaneous shocks of lost jobs, disintegrating nuclear families, and rising deaths of despair in their communities. As 20th-century institutions have crumbled around them, these men have withdrawn from organized religion. Their marriage rates have fallen in lockstep with their church attendance. Far from the ordered progression of the mid-century American archetype—marriage, career, house and yard—men without college degrees are more likely to live what Edin and other researchers call “haphazard” lives, detached from family, faith, and work.

This male haphazardness might be reproducing itself among younger generations of men who lack stable role models to point the way to college. Single-parent households have grown significantly more common in the past half century, and 80 percent of those are headed by mothers. This is in part because men are more likely to be incarcerated; more than 90 percent of federal inmates, for example, are men. Men are also less likely to be fixtures of boys’ elementary-school experience; about 75 percent of public-school teachers are female. Suggesting that women can’t teach boys would be absurd. But the absence of male teachers might be part of a broader absence of men in low-income areas who can model the path to college for boys who are looking for direction.