It took more than a decade, but the pendulum is finally swinging back from the rigid "zero-tolerance" policies adopted by school districts nationwide following the 1999 Columbine school massacre. Last week's unanimous ruling by Maryland's State Board of Education banned "zero tolerance," requiring the state's 24 school districts to adopt a more rehabilitative approach to discipline on a case-by-case basis and to use suspensions and expulsions only as a last resort.

This should have been the policy all along. A 2008 study found little proof that zero-tolerance policies increased school safety. But there's ample evidence that they've undermined educators' authority and credibility -- for example, by criminalizing minor infractions and redefining butter knives and spitballs as dangerous weapons. The Bethesda-based National Association of School Psychologists noted that such polices result in a higher rate of repeat suspensions, indicating they are "ineffective in changing behavior for challenging students."

The Examiner's Lisa Gartner reported that of the 8 percent of Maryland students suspended or expelled during the 2010-11 school year, more than half were kicked out for nonviolent offenses such as disrupting class. In May, the state board reversed the April 2011 suspensions of two Easton High School students for possession of "deadly weapons" found in their lacrosse bags -- which turned out to be a penknife one boy used to cut the strings on his lacrosse stick and a lighter the other used to cauterize the ends so they didn't unravel, which school administrators referred to as an "explosive device."

Talbot County was ordered to expunge the suspensions from the boys' school records. Rutherford Institute President John Whitehead, who appealed the suspensions, called it "a victory of reason and fairness over the kind of hysterical, irrational exercise of authority that teaches children to fear those in power."

Following state review and a public comment period, Maryland's new discipline policy is expected to cut suspensions for nonviolent behavior by more than a third, keeping more kids in school where they belong. Educators must also start tracking disciplinary measures to make sure that minority and special education students are not receiving harsher punishments for the same infractions, something else they should have been doing all along. But better late than never.