Yugoslavia's Serbs have responded to this spring's outburst of Albanian nationalism in Kosovo with a nationalism of their own. The Serbs have always considered themselves Yugoslavia's "political backbone." This, more than anything else, explains their violent reaction to the explosion of Albanian feeling in the southern Yugoslav province of Kosovo.
It also explains the severity with which ringleaders are being punished and the province's institutions purged. Unquestionably the pattern is dictated from Serbian Belgrade, whatever the supposed local autonomy.
Already some 100 demonstrators have been tried. The last batch of defendants received sentences of up to 15 years, the heaviest terms meted out in Yugoslavia since the war-crimes and collaborationist trials after 1945.
Unless restraints are applied soon, this exaggerated and nationalistic reaction may cause even more trouble for the Yugoslav federation. So says a reliable observer long familiar with the province.
He describes the attitude of the 1.2 million Albanians who make up 77 percent of Kosovo's population as "sullen and, for the time being, subdued -- but still simmering only just below the surface."
Little is known about the trials themselves. The proceedings are less open and the defense more limited than has been usual Yugoslav practice in recent years.
In addition to the harsh sentences being meted out, official measures being formulated against former administrators, regional chiefs of the Communist Party , and economic managers could well serve to keep ethnic passions alive. So could the drastic changes planned for education.
When education "took off" in Kosovo Province with the opening of a university and more high schools a decade ago, there were few Albanian-language textbooks and little source material. Neighboring Albania supplied both.
Now all such contacts and exchanges have been severed by the Yugoslavs, on the presumption that the Albanian government used them to "feed" ethnic resentment in Kosovo.
But the mainspring of Kosovo's revolt was clearly Belgrade's failure to perceive that the carrot of economic aid was no answer to nationalistic demands -- for example, to a separate ethnic-Albanian republic on an equal footing with the others in Yugoslavia.
Replacing Albanian textbooks with translations from Serbian ones and enforcing the dual-language requirement in Kosovo classrooms seems likely to make young Albanian Yugoslavs remember their grandfathers' time, when Serbian was the only language permitted.
Even the Croatian member of Yugoslavia's nine-member presidency has warned that the runaway campaign in the Belgrade news media and elsewhere against Kosovo Albanians could have grave consequences for all.Vladimir Bakaric told other top Croatian officials that information about Kosovo events was being "turned into a full-fledged incitement against the Albanians."
Dr. Bakaric is the last surviving elder statesman of the Tito era. He knows that this challenge to the nation's unity -- and the still more formidable threat of Serb nationalism -- comes at a time when Yugoslavia as a whole is suffering from economic problems that could fuel worse domestic tensions between its advanced and backward republics.
Yugoslavia's financial problems are unhealthily akin to Poland's. Its foreign debts this year will reach $20 billion -- only $7 billion less than the Poles'.
Only its independence and an open, reislient society stand between Yugoslavia and a Polish-style crisis.
Against this economic background, the gap between the advanced, richer republics -- Serbia as well as Croatia and Slovenia -- and the backward, exemplified by Kosovo, is bound to increase. So will the nationalism of an Albanian population feeling itself deprived, and the Serbian backlash that would not leave Croats, Slovenes, and others unmoved.