Fervent nationalism is rearing its head again in Yugoslavia's self-governing republics and semiautonomous regions. This was illustrated in events surrounding a play called ''Pigeon Hole,'' staged in Voivodina, a Serb-majority region of Yugoslavia. The play is named after a locality identified with a massacre of Serbs in wartime.
The play has been assailed by the Communist Party as ''fascist'' and evocative of ''dangerous nationalism.'' It has also brought furious condemnation from nearby Croatia and elsewhere. But ''Pigeon Hole'' continued its run.
Controversy about the play and about a ''threat'' of Serb nationalism in general still rages inside as well as outside the party.
Even a small show of ''greater Serbism'' raises the hackles of other ethnic groups.
Strong nationalist sentiment was a problem in Croatia in 1970 and in mainly Albanian-populated Kosovo in 1981. In 1970, Marshal Tito was on hand to calm regional pressures. But in 1981 he was not, and Kosovo became a center of conflict between Yugoslavia and neighboring Albania.
The region put a match to the powder of a highly emotional Serb nationalism that is never far below the surface.
There are a million Albanians in Kosovo. To them, Serbs in Kosovo represent colonialism. But to Serbs, Kosovo is the cradle of their Orthodox faith.
Serbs, in fact, are spread over much of Yugoslavia. Only 60 percent of Yugoslavia's 8 million Serbs actually live in Serbia. They still consider themselves to be the political backbone of Yugoslavia, as they undoubtedly were before World War II.
Current rising nationalism in Croatia has not yet reached the pitch of a decade ago. But the Serbs' opposition to the Albanians' claim to greater autonomy in Kosovo - encouraged by Serb politicians and churchmen and by well-known writers and a stream of lavish books on Serbia's medieval history - could push things too far.
And, without the authority of a Tito on hand to cope, the hazards to the federation could be greater.