This conclusion is supported by case studies of the nature and effects of street-level drug crackdowns, with particular attention to efforts in Lynn, Mass. The four purposes of retail drug enforcement are to maintain order, improve relations between the police and the community, suppress drug consumption, and reduce property crime. Any drug dealing which destabilizes a neighborhood may be worth breaking up. Whether such enforcement action depresses consumption will depend on the extent of the drug dealing and how easily users can switch from buying small quantities frequently to buying in bulk occasionally. Whether enforcement reduces property crime depends both on its ability to reduce consumption and on the share of consumption financed by such crime. The fact that cocaine is now being detected in the urine of about half of all arrested persons in New York City and Washington, D.C., suggests a closer cocaine-crime link than many had suspected. The disruption of street marijuana dealing is not likely to impact consumption significantly, since marijuana is cheap enough to buy in bulk, and users are less likely to consume their entire supply at one sitting.