CAMP PENDLETON --Both Marines are corporals. Both are fire-team leaders. And both are accused of playing key roles in a plot to kidnap and kill an Iraqi, and both men are heading to court-martial this summer.

But while the jury for Cpl. Trent Thomas will hear that five of his co-defendants struck plea deals and got light jail sentences in exchange for their testimony, the jury for Cpl. Marshall Magincalda will not be allowed to hear that same information -- even though it appears that the prosecution cases rest heavily on the testimony of the convicted men.

The reason? Two military judges made the disparate rulings, and judges have discretion over what is admissible in trial.

"On a case-by-case basis, the judges can make that determination," Kathleen Duignan, executive director of the National Institute of Military Justice, said of what is deemed OK for a jury's ears.

"It's happened to me," said Duignan, a former military attorney. "It's not as unusual as you would think."

Prosecutors say that Thomas, Magincalda and six other Camp Pendleton troops assigned to the 3rd Battalion, 5th Marine Regiment dragged Hashim Ibrahim Awad out of his home in the rural village of Hamdania on April 26, 2006.

The squad of eight is accused of killing Awad and then staging the scene to frame Awad as an insurgent planting a bomb.

Thomas and Magincalda have pleaded not guilty to charges of premeditated murder, kidnapping, conspiracy and related offenses in the death of Awad. A third Marine, squad leader Sgt. Lawrence Hutchins, has not yet entered a formal plea.

The three Marines, all of whom face courts-martial this summer, are being tried separately. All three face life in prison if convicted of premeditated murder.

The five other squad members accused in the case reached plea agreements with prosecutors and were given jail terms ranging from one to eight years. One of the men, Navy Corpsman Melson Bacos, has already served his time and been released.

In exchange for the light sentences, the five men also agreed to testify against their squad mates.

With the courts-martial looming, defense attorneys for Thomas and Magincalda told the judge in their respective cases that the jury should hear about the shorter sentences. They contend that the government bought the men's testimony in exchange for sweet deals.

Thomas and Magincalda got different answers to the same request.

Three weeks ago, Lt. Col. David Jones found that it was "crucial and essential" to Thomas' defense for the jury to hear about the light sentence given to co-defendants.

But Lt. Col. Eugene Robinson this week rejected the same request from Magincalda, finding that the plea deal specifics were not relevant, and that it might confuse the jurors.

Military law allows a judge to keep relevant evidence from the jury if the judge deems that it would do more harm than good to the case.

Among the permissible reasons for keeping evidence out of a trial is the danger that it would confuse the issues, mislead the jury or unfairly affect the case.

Duignan said the argument that Magincalda's judge abused his discretion could come up in Magincalda's appeal, if the corporal is convicted.

"The judge has a lot of discretion," Duignan said. "The court looks to see if the judge abused it -- and it is very difficult to show. There would have to be some kind of egregious effect."

One of the areas the appeals court would look at, she said, is any disparate results in the outcome of Thomas' case versus Magincalda's case.

Still, even if there are vast differences in the outcomes, it may not be enough to convince the appeal court that either trial judge's decision was unfair.

"Sometimes courts are persuaded by that," Duignan said of disparate results, "and sometimes not."