WHILE THE DEBATE over gay matrimony has once again placed the "sanctity of marriage" at the center of public policy discussions, a new study from the National Bureau of Economic Research suggests that easy divorce provides some real social benefits--even for couples who stay hitched. The study "Bargaining in the Shadow of the Law," by economists Betsey Stevenson and Justin Wolfers, finds that declines in three social scourges--female suicide, wife abuse, and murder of women by their husbands--are associated with the adoption of no-fault or "unilateral" divorces in most U.S. states.

In the 37 states that adopted no-fault divorce in the early 1970S (all but five states now allow unilateral divorce), female suicide has fallen by 5 percent to 10 percent, spousal abuse has dropped by about a third, and murder of wives has declined by about 10 percent. One explanation for these declines is obvious: Wives now have more freedom to exit bad relationships. Stevenson and Wolfers also consider "bargaining and distribution within marriage" in particular the way the threat of easy divorce increases the power of the dissatisfied partner to get his or her (usually her) demands met.

Whether these changes have increased the overall happiness of American marriages is a question even Dr. Phil might find hard to answer. But reducing the number of beatings, murders, and suicides is argument enough for the value of making marriages easier to exit.