Agreement on limited immunity between special prosecutor Lawrence E. Walsh and members of two select congressional committees removes what might have become a significant obstacle to Mr. Walsh's criminal investigation of the Iran-contra affair. The agreement to delay public testimony by Vice Adm. John Poindexter and Lt. Col. Oliver North for at least 90 days gives Walsh critical time to gather independent evidence.
At the same time, Congress will quietly move forward with its inquiry. Members of the House and Senate Iran-contra committees approved on Wednesday a compromise formula that permits them to grant limited immunity to Admiral Poindexter, President Reagan's former national-security adviser. Under the agreement, the grant may be made within the next month or two, but public testimony will not be taken until at least mid-June.
The committees also decided to delay for 90 days a decision on whether to grant limited immunity Colonel North, Poindexter's former National Security Council aide.
The controversy over the limited immunity question has focused primarily on North and Poindexter, and has sparked concern that Congress, in its desire to quickly expose the details of the Iran-contra affair, might harm Walsh's criminal probe.
While the committees are not expected to begin holding their joint public hearings until May 5, committee staff members and investigators will continue gathering evidence and taking testimony in private.
Under the limited immunity agreement, Poindexter is expected to be asked to appear in closed hearings with committee members as early as May 2.
The committees have already granted immunity to four relatively minor participants in the affair, and on Wednesday agreed to similar arrangements for six others.
The special prosecutor would not be able to use testimony given by North and Poindexter under limited immunity to build a case against them. Evidence gathered independently of the congressional testimony could be used.
Special prosecutor Walsh is hoping to gather enough evidence to support indictments prior to Congress's granting of immunity. The evidence would then be placed under seal by a court to prove without question that it had been gathered prior to, and without the assistance of, the immunized testimony.