Second, if we want lower-income Americans to have stable family lives, our political system should take family policy seriously, and look for ways to make it easier for parents to manage work-life balance when their kids are young. There are left-wing approaches to this issue (European-style family-leave requirements) and right-wing approaches (a larger child tax credit). Neither is currently on the national agenda; both should be.

Third, if we expect less-educated Americans to compete with low-wage workers in Asia and Latin America, we shouldn’t be welcoming millions of immigrants who compete with them domestically as well. Immigration benefits the economy over all, but it can lower wages and disrupt communities, and there’s no reason to ask an already-burdened working class to bear these costs alone. Here the leading Republican candidates have the right idea: We should welcome more high-skilled immigrants, while making it as hard as possible for employers to hire low-skilled workers off the books.

Finally, if we want low-income men to be marriageable, employable and law-abiding, we should work to reduce incarceration rates. Prison is a school for crime and an anchor on advancement, and there’s a large body of research — from scholars like U.C.L.A.’s Mark Kleiman and Berkeley’s Franklin E. Zimring — suggesting that swift, certain punishment and larger police forces can do as much to keep crime low as the more draconian approach to sentencing that our justice system often takes.