Washington — From the time of Sparta, women have sometimes played major roles in the military affairs of nations. Today they can be found piloting jets catapulted from the decks of aircraft carriers. Or, like Margaret Thatcher, they may lead a nation that is at war.
Yet most women have not only been excluded from matters of war fighting, but view the ''art'' - and especially its results - from a very different perspective. Judging by opinion surveys, they are consistently less likely to support a military buildup (especially if it comes at the expense of social services) or a more muscular foreign policy, such as exhibited by the Reagan administration.
This was most evident at a recent ''Women's Leadership Conference on National Security,'' attended by several hundred women who are elected officials, business and church leaders, educators, and representatives of major groups ranging from the Girl Scouts to the National Federation of Business and Professional Women.
The conference, organized by the Committee for National Security (a relatively liberal Washington group) and supported by the Rockefeller and Ford Foundations, drew the curious and the committed, the novice and the expert, from 33 states and a broad spectrum of political coloration.
The underlying theme, as conference organizer Anne Cahn put it, was ''to demythologize, to demystify these issues.''
''National security has become a women's issue,'' said Mrs. Cahn, a mother of three and former official with the US Arms Control and Disarmament Agency. ''It really comes down to war and peace and your children going off to war. Women relate to that in a very personal way.''
Many women seemed uneasy when Rep. Marjorie Holt (R) of Maryland, a member of the House Armed Services Committee, outlined a pattern of Soviet military influence and argued for a strong US defense posture. They were more enthusiastic in their response to Utah state Sen. Frances Farley, who led the successful fight to block the MX missile race track plan.
There was much talk about ''validating our intuitions and emotions,'' as Jane Leiper of the National Council of Churches put it, of realizing that ''sentiment and sentimentality are very different things.''
But the women here were also told that they must become familiar with much of the detail of defense strategy, tactics, and weapons systems if they are to influence Pentagon spending and operations.
''If you're going to get major changes in or an understanding of what drives the defense budget, you have to focus on the threat and what's to be done about it,'' urged Alice M. Rivlin, director of the Congressional Budget Office.
''You have to learn enough to formulate an opinion of your own, hold to it in the face of opposition, and educate others,'' said Sheila Tobias, author of ''Overcoming Math Anxiety'' and co-author of ''What Kinds of Guns Are They Buying for Your Butter? A Beginner's Guide to Defense, Weaponry, and Military Spending'' (to be published this fall).
While the number of women who take a professional interest in military matters remains relatively small, that may change as national-security issues gain broader interest. The current issue of Ms. magazine has an article titled ''An Intelligent Woman's Guide to the Military Mind,'' which discusses in some detail such things as the MX missile, B-1 bomber, and M-1 tank. Last month's McCall's magazine featured a long article on children's fear of nuclear war.
''Certainly I think that in this day and age we need to do what we can to help young people understand these issues,'' said Betty Pilsbury of Laurens, S.C., first vice-president of the Girl Scouts of the USA. ''Our youth have got to come up with answers for the future.''
Echoing other public officials, Mayor Eleanor Kesim of Elkhart, Ind., talked of the 12.9 percent unemployment rate in her city and of the diverting of public funds from public works projects to the Pentagon.
It remains to be seen whether women can ''reorder the priorities,'' as Mary Grefe, former president of the American Association of University Women, put it. But many of the leaders left intending to do just that.