Unilateral divorce laws caused temporary spike in violent crime

The research found an average 9 percent increase in violent crime after a state enacted a unilateral divorce law, which allows one spouse to end a marriage without the consent of the other. The increase in crime was mainly confined to the first two decades after the reform and was mostly attributable to individuals who were young children at the time the reform was enacted.

The link between unilateral reform and crime appears to be poverty and worsening in income distribution, say the study's authors, economists Julio Cáceres-Delpiano (Universidad Carlos III, Madrid) and Eugenio Giolito (Universidad Alberto Hurtado, Santiago, Chile).

"Mothers in adopting states were more likely to become the head of the household [after the reform] and to fall below the poverty line, especially less educated ones," they write. "Therefore, our results suggest that a potential channel linking unilateral reform with the increase in crime might have been the worsening in economic conditions of mothers and the increase in income inequality as unintended consequences of the reform."

The researchers used FBI crime reports from 1965 to 1996 for states that enacted unilateral reform during that period.

Unilateral divorce has been the subject of much study since a series of states started allowing it in the 1970s. Some researchers suggested that the reform caused a substantial and permanent uptick in divorce rates. But more recent research has shown divorce rates jumped in the first 10 years after reform, but the effects dissipated after that.

Cáceres-Delpiano's and Giolito's results bolster the notion that the effects of reform on the number of divorces -- and the social ills that accompany divorce -- were short-term, mainly affecting "families 'trapped' in that transition" to unilateral divorce, the researchers say.

How might the temporary nature of the effects be explained? Some researchers suggest that people changed their approach to marriage once the laws were on the books. "Scholars suggest that the reform has caused changes in the selection into and out of marriage, increasing the average match quality of new and surviving marriages," Cáceres-Delpiano and Giolito write.