Socialist Party's honeymoon with Spain continues

After six months in power, the honeymoon for Spain's Socialists is clearly not over. Sunday's elections at both the municipal and regional level indicate that support for the Socialist government of Prime Minister Felipe Gonzalez has waned only slightly after six months in office.

Socialists swept the municipal elections, obtaining 43.4 percent of the vote, based on tabulation early Monday of 90 percent of voting returns. This means the Socialists are firmly entrenched at both the national and regional levels - and now have the largest parliamentary majority in Western Europe.

Socialists obtained an absolute majority in 26 of the 52 provinces, and a relative majority in another 7. They also won landslide victories in 11 of the 13 autonomous communities.

The right-wing Popular Alliance coalition came in a distant second in the election, picking up an absolute majority in five provinces, a relative majority in three, and an absolute majority in two autonomous communities.

As in October's general election - which the Socialists won with 48.4 percent of the vote - the center parties, which have governed in the past, generally fizzled, and in some cases almost disappeared. Fringe parties diminished, reinforcing a two-party system of conservatives and progressives.

When the results became clear, Mr. Gonzalez, whose popular image and prestige were not tapped in the campaign, congratulated all the winners and promised to collaborate with all mayors, regardless of party affiliation. Appearing almost apologetic for the landslide Socialist win, Gonzalez insisted that democracy was not in danger even if the Socialists dominate the Cortes (national parliament), regional parliaments, and city halls.

Manuel Fraga, leader of the opposition Popular Alliance and a one-time member of Francisco Franco's Cabinet, expressed satisfaction about the vote. The alliance showed a slight improvement over October's election results.

The Socialists picked up an easy absolute majority in Madrid, and a near absolute majority in Barcelona. In Catalonia, the Socialists obtained victories in the ''red belt'' of industrial suburbs surrounding Barcelona, formerly controlled by the Communist Party. The conservative nationalist party in Catalonia, Convergencia I Unio, gained only slightly over 1979 local elections results.

On a national level, the Communist Party saw its votes dwindle from 10.8 percent held in the 1979 local elections to 8 percent in tabulations Monday. While disappointing to the Communists, it was nothing like the disaster in October, when the Communists won only 4 percent. (In 1979, the strong Communist showing led to Socialist-Communist coalition governments in most of Spain's cities.)

The only capital to have a Communist mayor, Cordoba, reelected him by a huge majority. ''Cordoba hasn't gone communist,'' said a bashful mayor elect, Julio Anguita Gonzalez. ''They just voted for a mayor who belongs to the Communist Party.''

The Socialist Party gained ground in the three troubled Basque provinces. The conservative Basque Nationalist Party lost some ground, though it maintained a slim majority in provincial capitals. The ultra-left-wing nationalist party Herri Batasuna, linked to the terrorist organization ETA, also lost ground in most Basque cities and towns.

ETA had expressly asked the population to vote, Herri Batasuna. Three days earlier it had claimed responsibility for three killings. Almost 60 percent of the industrial Basque suburbs clustered around the Nervion River switched from Basque Nationalist Party control to a Socialist majority.