Madrid — The Spanish Socialist Workers' Party, with an eye on socialist victories in Greece and France, has reaffirmed moderate positions at its convention, which ended Oct. 24.
Hoping to take advantage of the impending unraveling of the ruling Democratic Center Union (UCD), the Spanish Socialists bent over backward to appear lamblike by promising:
* To strengthen democratic institutions.
* To promote a market economy.
* To avoid nationalizations.
* To modernize the armed forces.
Under the symbol of a closed fist holding a rose, the moderate non-Marxist platform of their charismatic leader, Felipe Gonzalez, was overwhelmingly endorsed.
There were only a few minor squabbles with the so-called Marxist minority ''critical sector'' who abandoned the convention disgusted and defeated. Optimistic delegates assured themselves that the next socialist victory in Europe was bound to be in Spain, confirming French President Francois Mitterrand's prediction of a socialist Mediterranean.
But even without the undeniable electoral aid of the Greek and French triumphs, the Spanish Socialists have been gaining, according to polls taken just before the Greek elections, and could very well win the next national elections, in 1983.
To the advantage of the Socialists, who demonstrated a notable decrease in internal tensions and conflicts, the UCD of Prime Minister Leopoldo Calvo Sotelo seems to have started to disintegrate. It has suffered a series of internal bickerings between elements of its rather explosive mixture of Social Democrats, Center Liberals, Christian Democrats, and renovated ex-Francoists.
Disenchanted voters are turning either to the Socialists who are only slightly to the left of the ruling party, or toward a more traditional conservative right headed by Manuel Fraga Iribarne of the Spanish Democratic Confederation. This tendency was clearly demonstrated in the regional elections of the northwestern region of Galicia Oct. 20, where the UCD lost its majority to favorite son Fraga.
After the trauma of the attempted military coup last February, the Socialist opposition party has tried to present an image of moderation and responsibility.
Conscientious efforts have been made to convince the business community of the Socialists' lamblike image - although the employers' association still claims to discern the big bad Marxist wolf lurking under innocent sheep's clothing.
On the other hand, the employers' association has lost confidence in the ruling party and has started efforts to organize ''the grand right'' to ward off the specter of a Spanish Mitterrand.
It is frantically trying to fortify what in other countries has always been a respectable conservative party, but which in Spain has been too tarnished by identification with the Franco dictatorship. Conservatives were too embarrassed to admit belonging to the right.
Nevertheless, the employers' association has braced itself for a Socialist victory. One prominent businessman rationalized that at least a Socialist triumph would have the positive effect of unifying the right.
Sociologically, the growth of new large middle classes over the past 15 years has created a large percentage of moderate center voters that have been almost evenly divided between the government party and the opposition Socialists.
Both parties' electoral platforms have varied only slightly from a wide moderate consensus. Terror of another civil war has contributed toward continual consensus politics and pacts between the different political parties.
In the last elections, a little over a third of Spanish voters elected the UCD, which ironically later adopted parts of the Socialist platform on several issues, and a little less than a third voted Socialist.
In the 1983 elections that many political observers feel could be precipitated and held earlier, the results might very well be reversed with the splintering of UCD into more conservative positions.
Polls taken early this month indicate that a little under a third of Spanish voters will opt for the UCD, if it is still hanging together, and a little over a third may convert Spain into the next part of a socialist Mediterranean.