TURKEY MAY HAVE a once-in-a-generation opening to treat its national cancer, the problem of its aggrieved Kurdish minority. The opportunity arises from the sensational turn taken by Abdullah Ocalan, captive leader of the Kurdish separatist movement, at the start of his treason trial. He offered to abandon 15 years of armed struggle in return for a place at the Turkish national political table.

Mr. Ocalan comes into court as the man widely held responsible for the death of thousands in the Kurds' war with the Turks. His conduct will have to be scrutinized to ensure it fits his newly professed conversion to democracy. A man who faces a sure conviction in a "security court" and a possible death sentence may have personal reasons to appease his jailers by offering to "serve the Turkish state."

In its current nationalistic passion, the Turkish establishment may be reluctant to take a "terrorist" at his word. No less on the Turkish than on the Kurdish side, politicians tend to be in thrall to constituencies of their own creating. The Turkish strategy of relentless military and political attack on even the mildest stirrings of Kurdish group feeling enjoys strong army support and considerable public popularity as well.

The trouble is that strategy dooms Turkey to a conflict that sets it at odds with the humane democratic values of the Western nations whose company it most values. Here lies the source of the Kurds' power: not in their military capabilities but in their capacity to draw the NATO-oriented Turkish armed forces into a dirty war against a deeply embedded guerrilla part of the general population.

For the Turks, accommodating the Kurds won't be easy. Kurds will ask first for cultural and linguistic rights, then -- some of them -- for autonomy and then for self-determination. Those who hesitate to set foot on this slippery slope are not being entirely arbitrary. They are, nonetheless, inviting trouble. They must balance the obligations of a sovereign state to its territorial integrity against the self-fulfillment craved by its ethnic elements. So far the Turkish authorities are taking a hard line. Friends of Turkey must hope it can muster the courage to broaden its perspective and to conduct an honest exploration of the Ocalan initiative.