Reversal of Fortunes?

Sometimes at dusk, sometimes at dawn, when the dim gray light shrouds them from the enemy, commandos of the mainly Muslim Bosnian army launch coordinated attacks on Serb positions. Using their advantage in manpower, the Bosnian troops pick their way around the enemy's heavy tanks and guns, ambushing troops or blasting through sparsely defended encampments.

In the course of two weeks, these new tactics have served the Bosnian government well: for the first time in 31 months of war, they are poking through the overextended lines of the Bosnian Serb army. Government forces have retaken 60 sq. mi. of territory from the Serbs near Bihac in the north, made significant gains around strategic Mount Igman overlooking the capital of Sarajevo and recaptured the town of Kupres and perhaps an additional 40 sq. mi. in central Bosnia.

A forlorn quartet of Bosnian Serb tanks abandoned in the mountains south of Sarajevo last week -- their fuel tanks parched dry and deserted by once proud Serb soldiers -- signaled critical changes on the frontlines as the Balkan war enters its third winter. The government's gains are still limited, but the string of tactical successes is sparking new reassessments about the conflict.

The Bosnians owe much of their reversal of fortune to the adoption of the successful guerrilla tactics used by Tito's communists in the former Yugoslavia almost a half-century ago. Bosnian army units, some with barely 100 men, began ambushing Serb forces at 16 different locations around the country. Instead of the frontal assaults that foundered against the Serbs' superior firepower, says U.N. spokesman Paul Risley in Zagreb, the Bosnians "are employing commando tactics to grab territory." The breadth of the government offensive has exposed how thin the Serb defenses are: reinforcements dispatched to the Bihac region came from Kupres, for example, leaving it largely undefended.

The new tactics caught the Bosnian Serbs, who had come to discount the Muslims' fighting ability, by surprise. Bosnian Serb soldiers have been demoralized by Serbian President Slobodan Milosevic's decision last August to close his border with Bosnia, cutting off fuel and spare parts for the Bosnian ! Serb army. Its longstanding edge in mobility and firepower -- a heavy-weapons arsenal 10 times as big as the Bosnian government's -- is diminishing as fuel and supplies dwindle. Less fuel also means fewer rotations back home, hurting morale.

At the same time, the Bosnian army has been helped by a renewed flow of weaponry from Iran and other countries. "If the Croats really opened the routes," says a middleman supplying the Bosnian troops, "we could even bring in tanks and heavy artillery. We have the money." The government has also revitalized its local defense industry, churning out automatic rifles, hand grenades and bullets.

The pincer campaign to seize Kupres marks the first time the Muslims and Croats have fought as allies since they agreed to work together last spring. A firm alliance, much encouraged by Washington, could enhance Bosnia's military might by widening supply routes and bringing in Croat artillery. But U.N. observers warn that Croat cooperation in Kupres may simply be opportunistic -- a chance to advance their own territorial objectives.