Former diplomat Averell Harriman has stepped into the charged rivalry between Washington and Moscow, and offered a refreshingly sober assessment of it. Mr. Harriman, American ambassador here during World War II, argues neither superpower seriously contemplates unleashing the nuclear war that each charges the other with tempting.
''I think the leaders of both countries realize that no one can win such a war,'' Mr. Harriman said after meeting with Soviet leader Yuri Andropov last week.
Mr. Harriman said he, therefore, sensed less immediate peril of nuclear confrontation than public remarks from both sides might imply. But overall, he added, relations between the two major powers are ''bad.''
His prescription for improved relations was decidedly modest in tone and careful in phrasing. He said he felt the main superpower objective must be ''to take some of the issues that are solvable and try to work them out. Often it seems we try to go at the unsolvable.''