Who knew? The modern left-liberal claims to care about the little guy, income inequality and all disparities in wealth. In fact one could say such people are obsessed with the distribution of wealth, yet they offer less than plausible explanations for why such disparities exist. Often they make the puzzling assertion that rich people cause poverty, as if what the rich have has been taken from the poor. This is the static view of an economy as a pie, where there is only so much to go around. In this world if you tax the rich more, spread the wealth around, as our most progressive president said, you’ll get less poverty.

But economies and people don’t work the way liberals wish they would. That’s why when I saw a piece at Slate, a reliably significantly left of center publication, that addresses family as one of the most important indicators of social mobility I was surprised. When I saw that the author is a visiting scholar at the conservative American Enterprise Institute I was no longer surprised, but was amazed Slate would publish such views.

The piece reviews a recent Harvard study called “Where is the Land of Opportunity.”

[The study] explores the community characteristics most likely to predict mobility for lower-income children. [It] specifically focuses on two outcomes: absolute mobility for lower-income children—that is, how far up the income ladder they move as adults; and relative mobility—that is, how far apart children who grew up rich and poor in the same community end up on the economic ladder as adults. When it comes to these measures of upward mobility in America, the new Harvard study asks: Which “factors are the strongest predictors of upward mobility in multiple variable regressions”?

They found that the most important predictor of social mobility is that “children raised in communities with high percentages of single mothers are significantly less likely to experience absolute and relative mobility.” Even more interesting is the effect single mother families have on the culture of such communities, whereby even the children of married parents in such communities suffer from economic stagnation. And the opposite holds as well; in communities with lots of married families the children of single mother households do better.

Other factors affecting social mobility include things liberals and conservatives can agree on, like racial and economic segregation, school quality, social capital and income inequality. Yet after almost 50 years of the federal “war on poverty” when lower income families, black, white and brown (see Charles Murray’s new book “Coming Apart: The State of White America, 1960-2010”), have been decimated, liberals are still reticent to admit that the two parent family, mom, dad, kids, is the most powerful socialization force in existence.