Independent counsel Lawrence Walsh Thursday selected fired National Security Council aide Oliver M. North as the first of four defendants to be tried in the Iran-Contra conspiracy case.

Walsh advised U.S. District Judge Gerhard A. Gesell of his decision to try North as the first defendant but also asked the judge to reconsider his decision ordering separate trials for North, former national security adviser John M. Poindexter and arms dealers Albert Hakim and Richard A. Secord.Walsh asked that Gesell order two dual-jury trials in which North and Poindexter would first be tried together and Hakim and Secord would then go to trial jointly.

Gesell had ruled that trying the four defendants jointly would prejudice their constitutional rights because of the inability to use the defendants' immunized congressional testimony as part of the defense.

Gesell had ordered separate trials to allow one defendant, for example North, to use Poindexter's congressional testimony as part of his defense.

"The government recognizes the need to safeguard such rights but submits that there are ways to accommodate those interests without imposing the tremendous burden of four sequential trials on the government and the judiciary," Walsh said in a brief filed with the court.

Walsh said that two juries could be empaneled to hear a joint trial of North and Poindexter without prejudicing each defendant's constitutional rights. "The evidence the government would offer at separate trials of North and Poindexter and of Secord and Hakim would be overlapping," Walsh said.

"The government submits that a joint trial of North and Poindexter and a joint trial of Secord and Hakim, each with two independent juries, offers clear advantages in terms of judicial efficiency, conservation of the government's resources and speedy adjudication of the cases."

Walsh said it would be more logical to try North and Poindexter together because they are accused of "using their positions of trust and power to facilitate and protect an illegal financial and logistical network" to divert U.S. arms sale profits to the Contras.

Secord and Hakim should be tried together, Walsh said, because they are accused of operating an illegal enterprise "to carry out activities forbidden to the government."