Last year, Tennessee adopted a law restricting the purchase of over-the-counter cold and allergy medications containing pseudoephedrine as part of an effort to rein in home cooking of the popular stimulant methamphetamine. The law limited purchases to no more than nine grams of pseudoephedrine in a 30-day period.

Police in East Tennessee's Marion County collected pharmacy records of pseudoephedrine purchases and compared them to lists of people previously arrested for cooking meth, then used those records to arrest more than 80 people in April on charges of promoting methamphetamine manufacture. At least 30 of them were accused of making multiple pseudoephedrine purchases that put them over the nine-gram limit. But now a judge has ruled that local prosecutors were misinterpreting the new law.

In an August 3 ruling, Circuit Court Judge Thomas Graham threw out cases against 30 defendants, saying that he read the law to mean that prosecutors cannot use multiple purchases to argue someone exceeded the nine-gram rule. "It is clear that since none of the purchases in these cases exceeded nine grams, the state simply cannot legally make a promotion case as to any of these defendants," he wrote. The law must apply to only a single purchase if it is to withstand a constitutional challenge for vagueness, he wrote.

Graham apparently listened to Public Defender Phil Condra, who argued in a June hearing that the law puts innocent consumers at risk because its vagueness allows police too much discretion in making arrests. Condra suggested that people could end up being arrested for buying match books or coffee filters or other common items that can be used in meth manufacture.

In an earlier filing, assistant Tennessee attorney general Preston Shipp scoffed at the notion. There was "no possibility of conviction of an innocent person who purchases, as the defendant suggests, two packages of coffee filters, with neither knowledge that it will be used to produce methamphetamine nor reckless disregard of its intended use," he wrote. But that wasn't enough to convince Judge Thomas.

The Associated Press reported Tuesday that the Tennessee attorney general's office will challenge the ruling. According to David McGovern, an assistant district attorney general for the 12th Judicial District, prosecutors will argue that the law applies to the "aggregate amount. We think it reads a little broader."