The State Department said yesterday that neither Secretary of State Edmund S. Muskie nor any other department official had been involved or informed in the final stages of President Carter's decision to order a modified U.S. strategy in a nuclear war with the Soviet Union.

Spokesman John Trattner, in the latest episode of a controversy over what Muskie knew or should have known about the new military doctrine also said it was "an accident of timing" that the secretary of state was not informed of the president's decision before it appeared in the press.

In an attempt to defuse Muskie's unhappiness over the issue, Deputy Assistant Secretary of Defense Walter Slocombe, one of those most intimately involved in the nuclear doctrine, flew to Maine and briefed the secretary of state yesterday. The acting chief of the State Department's Bureau of Political-Military Affairs, David C. Gompert, will present the Foggy Bottom view to Muskie at his home in Maine today.

White House press secretary Jody Powell, said it was "a concidence based on his schedule" that Muskie had not been briefed before newspaper stories on the U.S. strategic doctrine appeared last Wednesday. But Powell was uncertain whether Muskie should have been involved in the final decision on Carter's directive, saying that this is a question that can only be answered by the president and his secretary of state.

White House, Defense Department and State Department officials all agreed that the presidential directive reflected a process of evolutionary development of U.S. war plans, rather than a sudden change, and that the State Department had been involved in interagency discussions in 1978 and 1979 as the directive took shape.

The State Department spokesman said, however, the "our last participation was toward the end of last year." Trattner added that nobody in the State Department had been aware that a presidential decision was imminent or had been made.

Carter's order, Presidential Directive 59, was signed July 25, according to official sources. The first that Muskie learned of it was in a conversation with Secretary of Defense Harold Brown and presidential assistant Zbigniew Brzezinski over lunch Aug. 5. At that time, according to various officials, Brown offered Muskie a briefing on the directive. By hi own account, however, Muskie did not get the impression that a presidential decision already had been made.

Press reports of the presidential decision appeared the next day in The Washington Post and The New York Times. Muskie was visibly upset when asked about the matter by reporters on his plane en route to California later in the day and appeared particularly concerned by a statement in the Times account that "neither the State Department nor the Arms Control and Disarmament Agency had been involved in formulating the [nuclear war] strategy."

It was still unclear yesterday why the State Department had not been involved in development of the plan's final stages, as the department had been in the earlier stages.

A government official who would not permit use of his name or affiliation said the later stages of the plan's development translated overall strategy into a directive on war planning that would not normally involve the State Department. A Defense official said he was unsure about the list of people to be consulted in the final phase because "it was essentially a National Security Council process."

State Department spokesman Trattner, reflecting a conversation with Muskie in Maine, said "the secretary feels the situation is now being rectified after the fact."

Muskie was not heard from directly. After several days' attendance starting late today at the Democratic National Convention in New York, he plans to be on vacation away from Washington until about Aug. 25.