In a ruling hailed as a victory by defense lawyers, a federal judge on Monday dismissed a money-laundering conspiracy charge against a prominent attorney accused of illegal dealings with a Colombian drug lord.

The issue was whether $5.2 million transferred from Colombia to the accounts of attorney Ben Kuehne were exempt from criminal prosecution because they were essentially legal fees. Kuehne's lawyers and defense attorneys' groups argued that the conspiracy charge against him violated the Sixth Amendment's guarantee that a person charged with a crime has a right to a lawyer.

U.S. District Judge Marcia Cooke agreed, rejecting the U.S. Justice Department's contention that the payments were not necessary for the defense of Colombian drug baron Fabio Ochoa, who was eventually convicted and sentenced to prison.

"Congress has explicitly exempted from the money-laundering statute transactions necessary to preserve a person's right to representation," Cooke said in a 13-page ruling. "If I were to construe the statutory exemption as the government suggests, the exemption for such transactions would amount to no exemption at all."

The National Association of Criminal Defense Lawyers, which filed briefs in the case, had argued that the conspiracy charge against Kuehne could deter lawyers around the country from representing numerous clients whose legal fees might stem from questionable sources.