Of all the intellectual and moral strengths possessed by Alva Myrdal, the 80-year-old co-winner of this year's Nobel Peace Prize, none is so striking as her resolve at age 60 to put those strengths to work for peace. She was eligible for retirement. Her marriage to Gunnar Myrdal, who was to become a Nobel economist in 1974, was happy. And she was celebrated in Sweden as a diplomat, teacher, author and pioneer feminist.

At 60, she was anything but an expert in the politics of peace. But that proved to be an invaluable piece of expertise in itself. She hadn't been dulled-out by years of debating the technicalities of disarmament. She understood that the specialists seldom get anywhere because their efforts at disarming have more to do with military strategies and outfoxing the wily "other side" than with finding a cure for a shared insanity.

In the modest manner of the 1980 Nobel peace winner, Adolfo Perez Esquivel, the Argentine pacifist, Myrdal said last week that her award had "symbolic importance . . . for all those who strive for a reduction in nuclear arms and a political relaxation in the world."

The comradeship of which Myrdal spoke includes, at least in the United States, a surprising number of women peacemakers. They are citizen activists like Randall Forsberg, who did much of the research when the nuclear-freeze campaign was just finding its way a few years ago into town referenda in New England; Ruth Sivard, the Leesburg, Va., military analyst whose annual reports on world military expenditures are as reliable as they are frightening; Rep. Patricia Schroeder (D-Colo.), who has been moving logically and inexorably to arouse Congress to the waste in the Pentagon budget; and several women's peace groups. Others like Joan Baez and Dr. Helen Caldicott come to mind.

The put-down for many of these women is that they are mere self-appointed intruders into high-stake policy matters. But the women have no choice but to appoint themselves. Who else will appoint them? A Ronald Reagan? A Jeremiah Denton? The intruder charge is even more baseless. Not to intrude -- to assume a passivity that lets the professionals have disarmament to themselves -- is to become an accomplice in militarism and take part in what Myrdal has called "a history of lost opportunities."

In 1976, Myrdal wrote "The Game of Disarmament: How the United States and Russia Run the Arms Race." Parts of the book have a personal tone, Myrdal presenting herself as though she is one woman talking to other women and men in a living-room circle.

She recalls that before 1962, when she became Sweden's representative in the Geneva Disarmament Committee, "I was not from the outset alert to the great risks of an incipient militarization of the world; I was not ready to cry out: Down with the weapons." But once she began reading and learning, "I was never able to stop the search for the why's and how's of something so senseless as the arms race."

The search was conducted from Sweden, which let Myrdal enjoy a natural ideological detachment. "During all my adult years," she writes, "I have been an interested observer and critic of the contortions of foreign policy. I felt there were better futures to choose than the ones of a Russian-led world revolution or an American-led stride forward to a century of unrestrained capitalism."

Forget localism, she advised. "My striving has been to widen the view to global proportions. And I firmly believe that trying to serve not your own country above others but mankind as a whole will in the long run serve the true interest of all nations."

Six years ago, when Myrdal wrote this powerful and enduring work, she confessed to being "near despair" over the weapons madness: "Something is fundamentally amiss when, even in democratic countries, disarmament can be such a dead issue." That has changed, both here and in Western Europe. The United States now has a nuclear-freeze campaign, with the issue being voted on next month in countless American polling booths. Much of the credit for this awakening is owed Alva Myrdal. More of us have been listening to her than she imagined