What is the human cost of measuring prison policy in cost-efficiency terms? Photographer: Noah Berger/Bloomberg.
What is the human cost of measuring prison policy in cost-efficiency terms? Photographer: Noah Berger/Bloomberg.

Nicholas Kristof's New York Times column this weekend offered a devastating account of America's mindless policy of mass incarceration. It also underlined a dangerous flaw in contemporary liberal rhetoric: using economic arguments to attack policies whose cardinal shortcoming is that they are morally wrong.

Kristof described the story of Edward Young, an ex-convict who was sentenced to 15 years with no chance of parole for being in possession of seven shotgun shells. Young's sentence is a travesty, as Kristof notes, because his four children will now grow up without their father, and society is no safer for it. U.S. Attorney General Eric Holder acknowledged the point Monday, when he announced that federal prosecutors will use their discretion to sidestep mandatory minimum rules in some cases.

But Kristof spends much of his column explaining the economic costs of policies such as the minimum sentencing laws that ensnared Young and his family. That includes the cost of 15 years in prison ($415,000), and the lower cost of other approaches such as job training and education.

"Almost everyone seems to acknowledge that locking up vast numbers of nonviolent offenders is a waste of money," Kristof writes. "Alternatives to incarceration are both cheaper and more efficient."

This is becoming a familiar tactic in liberal politics. The authors of Obamacare stress the law's potential to control costs as much as the prospect of health insurance for millions who couldn't afford it otherwise. Proponents of immigration reform focus not on the injustice of ripping people away from their families but on the value of new tax revenue. Climate change advocates stress the economic costs of inaction as much as the small matter of rendering the planet uninhabitable.

It's easy to see why proponents of these causes would rely on economic arguments: By appealing to people's wallets, they hope to give their message a deeper resonance. And it lets liberals push back against the familiar refrain that they're naïve about what motivates people, or that their hearts are getting in the way of their heads.

But the approach used by Kristof and others risks legitimizing the view that morality and economics are equally important factors in deciding which policy is appropriate and which isn't. To grasp the danger of that idea, imagine that long prison sentences for trivial offenses cost taxpayers less than education, rehabilitation or job training. Would the appropriate approach then be to expand those policies? Would sending Young to jail for 15 years be less offensive if it were cheaper? If rising sea levels were somehow a net plus for the economy, would environmental advocates work less hard to prevent them?

These aren't abstract questions. Washington is full of consulting firms that will provide economic data to justify any policy preference, so what seems like an unassailable quantitative argument can and will be challenged, even if that challenge is baseless.

Obviously, that's not to say economics shouldn’t play a role in policy decisions. But economics is better at helping us choose among various options for fixing a problem (Carbon tax or cap-and-trade? Private subsidies or expanded Medicare?) rather than whether to address it at all. Conservatives often acknowledge that values trump economics; why should liberals be so sheepish about admitting the same?

It's not impossible. In his remarks yesterday, Holder made only passing references to cost, focusing instead on American values. Kristof and others should follow his lead.

(Christopher Flavelle is a member of Bloomberg View's editorial board. Follow him on Twitter.)