Bonn — Rebellious left-wing Social Democracts came in like lions over the past several months. But they went out from the April 19-23 party convention, if not like lambs, then at least like outmaneuvered lions.
In the run-up to the Munich Social Democratic Party (SPD) convention, a goodly number of regional party conferences passed resolutions for unilateral Western restraint on nuclear arms that displeased SPD Chancellor Helmut Schmidt (and the United States). Some of the SPD chapters did so immediately after hearing impassioned pleas to support government policy from Mr. Schmidt's supporters or even Schmidt himself.
At the Munich convention the anti-weapons' efforts failed, however. As of this writing, a defense policy statement that didn't embarrass the government was close to being adopted.
In the convention debate on April 22 the maverick resolutions among the more than 300 defense alternatives raised from the floor - against new NATO (but not existing Soviet) nuclear weapons, for nuclear-free zones in Europe (but not the Soviet Union), or for a weapons' moratorium that the Bonn government argues would freeze current Soviet superiority in Europe - were defeated for the time being.
The real party confrontation on the issue has been postponed until a party conference in a year and a half.
This timing will place the SPD showdown just prior to the first stationing of new NATO missiles in West Germany if the current Soviet-American arms-control negotiations in Geneva do not lead to mutually agreed limitations.
With the SPD vote Schmidt has won a little respite. He has contended all along that some NATO response was needed to the roughly 200 SS-20 mobile missiles targeted on Europe that the Soviet Union has deployed since 1977. He has also maintained that if West Germany renounced new NATO missiles unilaterally at this point, it would remove any Soviet incentive to compromise on binding mutual limits at Geneva.
The cost of Schmidt's victory at the SPD convention was not altogether to America's or France's liking.
The SPD call for a moratorium on deploying short-range nuclear weapons (which the Russians are on the verge of doing but NATO is not) is fine. So are the endorsing of the NATO alliance and an East-West military balance, and the call on the Soviet Union to dismantle its SS-20s so that NATO would not have to deploy its new missiles.
The US, however, would have preferred something stronger than the final resolution's assertion that ''there must be no stationing on German soil before the SPD has fixed its opinion about the prevailing result'' of the Geneva talks. By contrast NATO and the West German and US governments are already committed to going ahead with deployment if no agreement is reached at Geneva no matter what the SPD might say in its platform.
Further, the SPD resolution specifically notes that French and British nuclear weapons should be counted in calculating the East-West nuclear balance in Europe. Both countries insist their independent nuclear capabilities may not be objects of US-Soviet negotiations.
In Munich the antinuclear forces are already starting to regroup. Three of their leaders were elected to the party executive committee and are going to fight hard for their cause between now and 1983. The SPD's youth wing - the Young Socialists - who had joined nonparty youth in demonstrating against new NATO weapons in Munich the weekend before the SPD convention, will continue to carry their cause to the streets. But for now party discipline and the postponement of the real party debate on nuclear weapons to next year have managed to get an unenthusiastic majority of convention delegates behind the Chancellor.
In the 18 months between now and the party showdown, the ''government wing'' of the SPD devoutly hopes that the pressures on it will have diminished. It hopes that Washington will have long since resumed strategic arms limitation talks with Moscow, and that President Reagan will have changed his macho image (which has scared Europeans).
Such a shift by Reagan could remove a strong stimulus to West German antinuclear protests while persuading the Reagan administration that European alarm about nuclear weapons doesn't necessarily signify appeasement of an anti-American bias.
West German government officials hope further that by fall of 1983 the West German antinuclear movement will have lost its political momentum. Already the Greens - the fledgling environmentalist party that is doing very well in state elections - has split off from communists within the peace movement. If the US is seen to be negotiating arms control seriously, much of the visceral fear and emotion that has fanned the European peace movements in the period since President Reagan's election could fade.