Serb forces lined up their heavy guns last week and blasted their way toward Bihac, the last of the lands in the northwest held by the Bosnian government. Then Yugoslav-made jets from a Serb airbase in Croatia joined in the attack. NATO fighter-bombers roared across the Adriatic from Italy to bomb the base, punching a few craters into the concrete runways, but carefully avoiding Serbian planes or soldiers. Two days later, when the Serbs failed to get the message, NATO planes hit two of their antiaircraft installations in Bosnia with missiles.
That did not stop the Serbs either. So U.N. military...