Prospective job applicants wait in line to learn about job openings during a job fair held by Kentucky Kingdom amusement park to hire seasonal summer workers in Louisville, Kentucky, U.S. on Saturday, Jan. 4, 2014. Companies added more workers than projected in December as U.S. employers grew more optimistic about the prospects for demand, a private report based on payrolls showed Jan. 8. Photographer: Luke Sharrett/Bloomberg
Prospective job applicants wait in line to learn about job openings during a job fair held by Kentucky Kingdom amusement park to hire seasonal summer workers in Louisville, Kentucky, U.S. on Saturday, Jan. 4, 2014. (Luke Sharrett/Bloomberg)

The law of unintended consequences has been a major stumbling block for the left. People, in all their infinite complexity and irrationality, refuse to behave in ways the government anticipates.

So we see with Obamacare. Looking at the latest Congressional Budget Office report, the left, given the talking point from the White House (I kid you not, this is the defense of Obamacare), says 2.5 million jobs aren’t going away, it’s millions of people who will leave the workforce and/or work less because they get free or subsidized healthcare. Now there’s a selling point — induced sloth to get government benefits.

The argument is peculiar because when it comes to unemployment insurance, the left insists the availability of benefits doesn’t deter people from working. In any event, with less people working, fewer hours being worked and lower take home pay America in the Obamacare era is resembling the economic nightmare Republicans insisted it would be.

But this is nothing new for the liberal welfare state. In a must-read piece Mona Charen  describes, “A paper by two MIT economists, ‘Wayward Sons,’ published by the center-left think tank Third Way, outlines the startling decline in the fortunes of moderately to poorly educated men over the past several decades. The title of the opening chapter is direct: ‘Women gain ground, men lose ground.’ Starting with the cohort born in 1951, a gender gap in high-school completion has opened up and continues to grow. More girls than boys are graduating from high school.” Some of that, maybe a lot, goes back to the atomization of the family prompted by the welfare state that allowed and in some cases encouraged women to be single mothers without a permanent male adult in the household. (“…the dramatic change in family structure since 1970. In that year, 69 percent of black men without a high-school diploma were married. By 2010, only 17 percent were. The marriage rate among non-college-attending whites and Hispanics has declined precipitously as well”).

Frankly we sometimes don’t know why trends come about. We are at a 30-year low in the abortion rate. Pro-choicers say use of  long-term contraception (is this new?) is the difference. Pro-lifers say it is restrictive abortion regulations. Maybe it is some of both, or maybe this is part of the longer-term trend about women putting off marriage (and relationships) to work on careers.

Nor is faulty prognostication anything new. In the 1970s many were convinced that demographic trends, widespread availability of drugs, heightened crime and the general decline in culture would leave our major cities like war zones. In fact, a revolution in policing defied predictions

Government shouldn’t do nothing, but we should proceed with humility about our ability to refashion society and with a deep appreciation for the social and behavioral factors that are sometimes outside government’s reach. No wonder conservative reformers concerned about maintaining a culture of work, the reduction in poverty and greater prosperity for all look askance at large social welfare schemes. They tend not to work out as advertised.

Jennifer Rubin writes the Right Turn blog for The Post, offering reported opinion from a conservative perspective.