When Is Enough Enough?

THE world has been shocked by images of UN officers held hostage by Serbs and handcuffed and chained to ammunition dumps and other targets in Bosnia. The soldiers should be released immediately. Lacking that, the White House, which engineered NATO airstrikes last week, should reveal ''Act Two.'' Having fired on the Serbs besieging Sarajevo, NATO must change the sad status quo of the UN mission and show resolve. At a minimum it should strictly enforce the 12-mile weapons exclusion zone around Sarajevo and protect the ''safe areas.'' Blatant Serb violations of those zones brought the airstrikes.

If there is no ultimatum to the Serbs, no serious plan to deliver on the guarantees that NATO made a year ago to protect civilians in Sarajevo and the safe areas, no ''Act Two'' -- then the White House has failed to show resolve or credible leadership. It will have actually aided the Serbs in their brutal years-long aggression. At this point, Serbs will read any desire to negotiate as weakness and capitulation, and will demand more spoils. This is unfair to the Bosnians. It will strain relations with Muslim countries in the United Nations, which want to take strong action. It sets terrible precedents for the future. The Serbs are murdering and terrorizing an entire country while representatives from the civilized West stand by and watch. Just when is enough enough?

Last week, many people were impressed when NATO planes hit a Serb ammunition dump, making a big cloud of smoke. Yet in truth this was another pinprick airstrike. What the public should know is that in recent weeks the Serbs have steadily undermined all NATO gains. They have killed dozens of civilians a day. They have used deadly phosphorus bombs on Sarajevo -- a violation of the Geneva Convention. They have killed many peacekeepers. On Thursday they massacred 71 Bosnian high school students when a shell exploded in Tuzla at a graduation celebration. They have shut off electricity and power to Sarajevo. On Sunday they killed the Bosnian foreign minister. In this context, pinprick airstrikes mean little.

Why were UN troops allowed to be in Serb territory before the airstrikes? Certainly UN officials knew that, as before, hostages would be taken.

If this latest hostage-taking is used to merely redeploy French troops, the Serbs may invade the safe areas. Then the White House airstrikes will truly have aided Serb leader Radovan Karadzic. Aiding war criminals is unacceptable for any civilization.