The fiasco was a blow to President Andres Pastrana, who took office six months ago, pledging ““change is now.’’ He declared a curfew and sent in 4,000 troops, who clashed repeatedly with roving gangs of looters even after relief supplies began to reach the majority of victims. Restoring the city, at a cost of some $500 million, could take years. Building trust in Pastrana’s government may be even harder.