LOBBYIST JACK ABRAMOFF pleaded guilty in 2006 to fraud and bribery charges as the leader of a scheme in which he ripped off Native American clients, plied public officials with all-expenses-paid luxury trips and pocketed tens of millions of dollars for himself. Mr. Abramoff, who agreed to pay millions in restitution, was sentenced to four years in prison.

Michael Scanlon, Mr. Abramoff’s right-hand man, and Robert Ney, a onetime Republican congressman implicated in the scandal, also entered guilty pleas. Mr. Scanlon was sentenced to 20 months, Mr. Ney to 30 months.

So what, according to the Justice Department, is the appropriate sentencing range for Kevin A. Ring, a lobbying associate of Mr. Abramoff who was convicted last year but never accused of personally benefiting from the scheme? A term of 17 to 22 years. One reason for the astronomical sentence, according to the government: Mr. Ring was the only lobbyist who went to trial instead of pleading guilty and cooperating with the United States.

The government backed off this assessment in a court filing last week, but only after a rebuke from Judge Ellen Segal Huvelle of the U.S. District Court for the District of Columbia. “Defendant’s position is that the government is retaliating against him for exercising his Sixth Amendment right to trial,” the judge wrote. “It is easy to see why such an inference might be justified,” she added, especially when the government agreed to far lesser sentences for those who were clearly more culpable.

Individuals who plead guilty and cooperate with the government are often given lighter sentences. A willingness to accept responsibility and to help law enforcement officials identify others involved in wrongdoing promotes an important public purpose and saves the courts time and money. There is a fine line between rewarding someone who cooperates and punishing another who chooses to seek vindication in court. The Justice Department crossed that line in Mr. Ring’s case.

The department calculated the sentencing range for Mr. Ring by amalgamating the value of all of the bribes paid in the scheme as well as the total dollar value of the benefits received by clients as a result of illicit activity. Federal sentencing guidelines allow such an approach and call for proportionately stiffer penalties as the dollar values rise. But, as Judge Huvelle pointed out, this methodology was not used for any of the other lobbyist co-conspirators. The Justice Department says it did not do so because it did not have a clear picture of the extent of the corruption when it struck deals years ago with other culprits; additional years of investigation and Mr. Ring’s trial helped to put the matter in sharper focus.

Judge Huvelle roundly rejected the government’s approach and concluded that the calculation of the dollar values involved was inflated and not reliable.

The government now says that 50 months — two months more than Mr. Abramoff’s sentence — would be fair. Mr. Ring is asking for five years’ probation. The judge has great latitude in this final stage of sentencing. Judge Huvelle, who is scheduled to formally sentence Mr. Ring at the end of this month, should ensure that he is held accountable for his serious crimes but not punished for choosing to challenge the government’s charges in court.