Church attendees become more likely to use drugs and drink heavily when states abolish "blue laws." So says a recent study, "The Church vs. the Mall: What Happens When Religion Faces Increased Secular Competition?" The study also found that weekly church attendance and church giving decline after states repeal blue laws, which restrict commerce and labor on Sundays.

"They aren't quitting whole hog," said Daniel Hungerman, a study author and assistant professor of economics at the University of Notre Dame. Instead, those who attend weekly might go monthly, and monthly attendees might show up just at Christmas and Easter. While church giving decreased, the study found other charities saw a corresponding increase in donations.

When a blue law is in place, non-church-goers are about 10 percent more likely to drink heavily than churchgoers. After blue laws are repealed, the gap closes to about 5 percent.

For marijuana and cocaine use, the gap nearly disappears. Non-churchgoers are 11 percent more likely to smoke pot while blue laws are in place. After repeal, the two groups look almost the same.

What's the connection? One possibility is that blue laws do what they set out to do, Hungerman said. They encourage Sabbath rest and church attendance while promoting moral behavior.

Sunday closing laws have been around in America since the 13 original colonies. By the late 1800s, blue laws were on the books almost everywhere, forbidding activities like playing baseball or changing wagon wheels on Sunday. The U.S. Supreme Court upheld blue laws as constitutional in a 1961 case, giving discretion to the states. Nevertheless, most states repealed the laws throughout the next 30 years, despite protests from Christians that the laws limited ...