U.S. appellate court Judge Irving R. Kaufman's position as head of the President's Commission on Organized Crime is being questioned after a federal appeals court ruling that service on the commission by U.S. judges is unconstitutional.

Voting 2 to 1 Wednesday, a panel of the 11th U.S. Circuit Court of Appeals said the separation of powers doctrine is violated when members of the judiciary serve on an executive branch commission whose duty is to improve prosecutorial tools.

Commission spokesman Arthur P. Brill Jr. said Kaufman would have no immediate comment. "We're studying the opinion and weighing our options . . . . In the meantime, it's going to be business as usual for the commission. We have a very important mandate to fulfill," he said.

A Justice Department source said that, when the post was discussed with Kaufman in 1983, the understanding was that he would take senior judicial status and end his active caseload to avoid a possible separation of powers violation.

The source said Kaufman insisted on continuing as an active judge and asked that the words "improvement in the administration of justice" be added to the commission's name. The title was not changed.

Also on the 19-member commission is Potter Stewart, who retired as a Supreme Court justice in 1981.

The 11th Circuit Court's decision said, "A judge who is charged with assisting and improving enforcement efforts against organized crime must adopt a pro-government perspective which is ill-suited to a judge's obligation to be neutral in the courtroom . . . .

"Even if a judge could satisfy himself that he could separate his participation on the commission from his judicial functions, it is not clear that litigants could sustain equal faith in his impartiality," the court said.

The court added, "These problems would seem to bear particularly on the participation of Judge Kaufman, who is both chairman of the commission and an active judge in a jurisdiction which has a well-publicized problem with organized crime."

Kaufman is a judge in the 2nd Judicial Circuit, which includes Connecticut, New York and Vermont.

The decision came in response to a case brought in Miami by Lorenzo Scaduto, a reputed organized-crime figure and convicted felon fighting a subpoena to testify before the commission. Scaduto, granted immunity, argued that he is not required to comply with the subpoena because the commission is improperly constituted.

A U.S. District Court in Miami found Scaduto in contempt of court and added a year of prison time to the 64-year sentence he is serving on federal drug charges. Scaduto appealed to the 11th Circuit Court.

Although the appeals court agreed that the commission is improperly constituted, it said that was not reason enough to invalidate the subpoena.

The majority of the appeals court panel left intact the commission's powers and previous actions. But Judge Frank Johnson took exception, saying, "I believe we have no choice but to hold all prior actions of the commission in its attempt to secure Scaduto's testimony invalid."

Judge Paul Roney disagreed with the majority on the separation of powers question and noted that judges have often served in executive positions without constitutional challenge.

For example, Robert H. Jackson took leave as a Supreme Court justice to serve as U.S. chief counsel at the Nuremberg war crimes trials in 1945 and 1946. Chief Justice Earl Warren headed the commission investigating the assassination of President John F. Kennedy.

In 1794, John Jay served simultaneously as chief justice of the United States and envoy to Great Britain, and in 1799, Oliver Ellsworth served as chief justice and envoy to France.