Washington — The issue of war and peace is evolving as one of the dominant public and political themes this summer. Among the more significant threads in this tapestry of concern:
* A key Senate committee Wednesday took up legislation to establish a United States Academy of Peace, and quick approval here is expected since most members are supporters. This is a perennial issue that until now (in the words of one of its sponsors) has been ''loved to death.'' But the measure now includes more than half of all senators as cosponsors, and the number of declared supporters in the House (145 at last count) grows almost daily.
So far, the Reagan administration opposes a peace academy. But as the 1984 election approaches, this may be just the symbol many politicians need to quell their unease over how the public may respond to efforts to move ahead on new nuclear weapons.
''The peace movement in America is profound,'' says one Republican lawmaker. ''The Republican Party at their peril ignores it.''
* Also this week, MX opponents launched what they call a ''major new lobbying effort to defeat the missile system.'' Congress so far has kept the strategic nuclear weapon alive. But House Speaker Thomas P. O'Neill Jr. (D) of Massachusetts has postponed a vote on missile procurement until July to give opponents more time to organize. Meanwhile, significant amendments are being added to the MX bill that would limit the Pentagon.
* Anti-nuclear activists plan protests this Father's Day weekend in 50 cities and 30 states. Later this summer, peace activists and others will gather in Washington to commemorate the 20th anniversary of Martin Luther King's ''I have a dream'' speech. The escalating arms race will be a major theme.
* The Roman Catholic Church, following the recent bishops pastoral letter on nuclear war and weapons, is telling its chaplains to assure their flocks in the military that the controversial missive need not necessarily present them with a moral dilemma over uniformed service. The bishops also endorse efforts to establish a peace academy.
This issue is one that has attracted both relative hawks on Capitol Hill and their more dovish colleagues.
In recent testimony, Sen. Roger W. Jepsen (R) of Iowa explained why there is no logical inconsistency in his support for increased defense spending (including money for the MX missile) and his being a principal cosponsor of the peace academy bill.
''Given the world in which we live, both could serve the same goals: the prevention and avoidance of war and bloodshed,'' he said.
Rep. Jim Leach, a fellow Republican from Iowa, is a peace academy sponsor in the House who is leading the opposition to the MX. A former foreign-service officer, Representative Leach disputes the current State Department argument that another government agency devoted to diplomacy and conflict resolution is unnecessary.
Both heartland Republicans are getting the clear message from their constituents to work harder to reduce superpower tensions and the likelihood of war.
''The size of the new public concern is wonderful,'' says Leach, speaking of the church deacons, women, community leaders, and other traditionally Republican groups supporting peace efforts. ''The new public efforts have made a lot of politicians squirm.''
In the third and final draft of their pastoral letter, US Roman Catholic bishops added an endorsement for a peace academy that speaks to much of the rest of grass-roots America: ''Such an academy would not only provide a center for peace studies and activities, but would also be tangible evidence of our nation's sincerity in its often-professed commitment to international peace and the abolition of war.''
Bills in the House and Senate would allot no more than $31 million total for the two years needed to establish a Washington-area US Academy of Peace. With a relatively small staff, this would act principally as a catalyst for existing public and private sources of research, education and training, and information on conflict resolution.
One of the bill's Senate cosponsors is Alan Cranston (D) of California, the presidential contender who has grasped the peace and anti-nuclear issue as his main theme. Senator Cranston was prominent among the politicians gathered on the steps of the Capitol Tuesday to rally against the MX missile.