IT is time to end the appeasement of the Sandinistas in Nicaragua.In the name of conciliation and tolerance, Violeta Barrios de Chamorro has made a string of concessions to the former communist rulers since Nicaraguans so emphatically dismissed them from office a little more than a year ago. But in a furious display of their continuing power, and their hostility toward reform, the Sandinistas ran wild last weekend, sacking anti-Sandinista radio stations, destroying government buildings, and harassing opponents. It was evidence, if ever any were needed, that the ousted Sandinistas are not working constructively for a democratic society, but are seeking to disrupt the process. Thus President Chamorro is reaping the bitter harvest of a policy of appeasement which the Sandinistas have cynically exploited. Though the weekend violence was ostensibly due to the desecration of a Sandinista leader's tomb, it in fact related to the large-scale Sandinista theft of government and private property before leaving office, and the ineffective efforts of the government to make them give it back. The Sandinistas robbed the national treasury, plundered government office buildings, and looted official property. They also seized thousands of acres of private property and private homes, mainly from their hapless political opponents. Fearful of the Sandinistas, Chamorro's government has dithered over enforcing the return of this property to its rightful owners. The government's weakness has been compounded by its early mistake in letting the Sandinistas retain control of the military and the police. Thus the government's ability to enforce its will is limited. During the weekend violence, for example, the Sandinista-run police force stood by and watched without intervening as Sandinista demonstrators went on their rampage. Chamorro and her advisers have argued that this kow-towing to the Sandinistas is necessary in the short term to ensure their participation in the passage to democracy. Critics within her own coalition, however, have branded it a policy of dangerous weakness, permitting the Sandinistas to retain and consolidate power. Foreign well-wishers of Chamorro, while paying tribute to a better human-rights climate in Nicaragua since the election, have also been concerned about her failure to resolve the dispute over private-property rights and her reluctance to keep the Army and police in check. In August an international fact-finding commission warned that the Sandinista armed forces "apply the law without rigor or consistency, routinely enforcing it only when it coincides with FSLN [Sandinista] policies and interests." The armed forces "operate as if they were above the law, using their power to persecute their ideological enemies ... and to serve their own interests and enrichment." The commission was sponsored by the Puebla Institute, a lay Roman Catholic human rights group; the American Institute for Free Labor Development, an AFL-CIO group fostering democratic trade unions; the Americas Society; and Freedom House, a New York-based human rights monitoring organization. The fact-finding commission declared that ownership of land, houses, companies, and assets in Nicaragua is often in doubt "because of a decade of Sandinista confiscations and nationalizations." The commission found that the land-registry office is controlled by "Sandinista partisans who favor Sandinista claims in cases of property disputes and who even now secretly change names on property titles, in effect continuing the practice of confiscations. Only a small portion of arbitrarily confiscated lands ha ve so far been returned to former owners." Indeed, last weekend Sandinista leader Daniel Ortega Saavedra warned the National Assembly and government not to require the Sandinistas to give back the land they acquired before they left office. This situation, warned the commission, is "fueling deep social discontent which, together with persecution by the Sandinista armed forces, has led some in the resistance to again take up arms." That is exactly what is happening as some of the former contras regroup and rearm. With a changed Soviet Union and an embattled Cuba, the Sandinistas today are not getting the support they used to from their communist mentors. But they remain a worrisome barrier across Nicaragua's road to peace and democracy.