A former drug counselor asked a Utah federal judge Friday to give him a new trial, claiming his attorney erred by not presenting evidence 13 ounces of marijuana seized by police could have been for his personal use.

"This is the one issue in the case: What is he doing with all those drugs?" said Harry Caston, the attorney handling the new trial motion for Grant S. Maxwell, 45, Salt Lake City.Maxwell was convicted on charges of drug possession with intent to distribute and use of a firearm in a drug trafficking case. He could be sentenced to up to 20 years in prison on the drug count, plus an additional minimum mandatory five-year term on the weapons charge.

But, if the drug charge were one of simple possession, federal Judge David Winder said, "There is no gun charge if there is no trafficking."

However, prosecutor Heather Cooke said she "had never yet seen" such an argument work. "It's an unsuccessful tactic."

Maxwell was drug counseling program coordinator for Charter Summit Hospital when he was arrested Oct. 29, 1988, after police found him unconscious inside a parked vehicle in Midvale. A search of his vehicle turned up the marijuana and a .22-caliber semiautomatic pistol.

Caston claimed Maxwell's trial attorney, Randy Cox, made a "crucial error" in failing to call psychiatric experts "to explain something absolutely crucial to the jury. I think the jury needs to know what is motivating the addict."