The onset of a long-delayed US-Soviet disarmament dialogue has eased transatlantic relations, made life easier for West German Chancellor Helmut Schmidt, and apparently confused the antinuclear peace movement.
Bonn has warmly welcomed President Reagan's May 9 speech at Eureka College, followed by this week's announcement that talks on the ''limitation and reduction of strategic nuclear arms'' will begin in Geneva on June 29. All this gives West German officials an opportunity to portray Mr. Reagan as a pioneer of peace.
But the start of talks will not halt a lively debate here about the future of nuclear strategy, centering on calls for a nuclear weapons freeze and for the West to renounce first use of atomic arms. Officials noted that apart from wresting the propaganda initiative back from the Russians with a proposal that looked bold and sounded simple, Mr. Reagan's Eureka speech had quietly dropped his previous insistence that talks be linked to worldwide Soviet ''good behavior.''
''The speech marked the transformation of Reagan from ideologue to realist,'' one of the chancellor's aides enthused. Mr. Schmidt felt he had succeeded in steering the fourth US administration in his eight years in office toward a more realistic approach to the Soviet Union.
Just how far Bonn's frustration had gone was shown by a chancellery policy study leaked to the press just before the Reagan speech. It urged Mr. Schmidt to take a public stance against neo-conservative foreign policy trends in the US and Britain even if this risks sparking more disputes with Washington.
The Eureka speech was appreciated here as a clever piece of timing. It means this month's Bonn NATO summit can end with a display of Western unity despite the transatlantic divisions over defense spending, economic ties with the Soviet bloc, and attitudes toward Poland that have marked the last year.
To West German delight, Secretary of State Alexander M. Haig Jr. agreed to a North Atlantic Council communique which stated that alongside deterrence, ''genuine detente through dialogue and negotiation'' was the goal of the Western alliance.
The formula left room for the Reagan administration's view that what happened in the 1970s was a false detente that Moscow exploited to expand its world power. But the very word ''detente'' was taboo until recently, and its inclusion was heralded as a triumph for West German interests by Foreign Minister Hans-Dietrich Genscher.
President Reagan's image here has not changed overnight. There will still be plenty of peace movement demonstrators on the streets of Bonn and West Berlin when he makes his first European trip June 2 to June 11.
But the latest spate of superpower ''peace mongering'' has all but silenced the best-known leaders of the peace movement and may undermine the credibility of some of their arguments. The movement, always a loosely knit coalition, has already been weakened by failure to find a unified response to martial law in Poland and by rows over the place of pro-communist groups in its midst.
Its attempts to forge links with antinuclear campaigners in the United States have had only limited success. While Pete Seeger and Joan Baez are happy to sing at European peace rallies, politicians like Sen. Edward M. Kennedy are aware of the potential domestic fallout from sharing a platform with left-wing European pacifists.
Senator Kennedy's campaign for a worldwide nuclear freeze, often misunderstood here, has won intense news media coverage. But the Bonn government seems more worried by the call of four American ''elder statesmen'' for a radical change in NATO strategy, renouncing the first use of nuclear arms.
Aides say Mr. Schmidt is worried that the peace movement may latch onto the ''no first use'' appeal published in the spring issue of Foreign Affairs of George F. Kennan, Robert S. McNamara, McGeorge Bundy, and Gerard Smith while ignoring the fact that they consider a vast strengthening of NATO's conventional forces to be a precondition for any such move.
Bonn officials regard the ''no first use'' proposal as utopian, since it would require defense spending increases that no West European government could push through in the present austere economic climate.
''Since NATO has no prospect of matching the Warsaw Pact in conventional forces, nuclear deterrence will remain essential for the foreseeable future,'' a senior Defense Ministry official said.
But the last two years of heightened East-West tension have set off a profound debate in West German society about the ethics and effectiveness of nuclear deterrence. Apart from the peace movement, experts in all three major West German parties are seeking alternatives to the present nuclear strategy that, in the words of Social Democratic security expert Egon Bahr, ''in the end amounts to threatening collective suicide.''
The freeze idea is attractive to all those who fear that military technology will otherwise once again overtake the slow diplomacy of arms control.
But in the long term, it is the ''no first use'' concept that poses the biggest challenge to NATO doctrine and that may prove most attractive to West Germans living on Europe's ideological border.