State law allows police to use underage volunteers to discover whether bartenders and liquor store clerks will sell booze to minors, the North Dakota Supreme Court ruled.

The decision Tuesday upholds the misdemeanor convictions of workers at two Bismarck convenience stores and a bar, each of whom sold beer to underage customers during a police check on April 1, 2005. They were given deferred sentences and ordered to pay almost $120 each in fines and costs.

In their appeal, the trio's attorney, Justin Vinje, argued the Legislature has not given local police authority to use underage decoys in sting operations to detect underage alcohol sales. North Dakota law forbids minors from going into bars and liquor stores.

The Supreme Court, in a unanimous ruling Tuesday, said the practice was justified by a 2001 state law that allows individuals to work under orders from a law officer, as long as they believe what they're asked to do is within the officer's authority.

"The legislative history of this (law) contains ample testimony showing the intent of this provision was to allow persons under 21 years of age to be used in alcohol compliance checks," says the court's unanimous opinion, written by Chief Justice Gerald VandeWalle.

"It is the Legislature's decision whether or not, as a matter of public policy, to allow law enforcement officials to conduct alcohol compliance checks in this manner," VandeWalle said. "The Legislature has decided to allow this conduct."

When doing the checks, underage buyers were told not to lie about their age and to display identification when asked to do so.