'Payback' feuds and 'eye-for-an-eye' killings, which underlie tribal fighting in Papua New Guinea, are a deeply entrenched tradition in the Highlanders' society. Where in the past, pig trespass, female disputes, and land availability were the causes of violent conflicts between tribes, now the profusion of consumer goods, modern living, vehicles, and cash provide even more perceived grounds for violent behavior. The original 1950's concept of diplomatic immunity for all using the government road system now makes it easier for clans to mobilize and for vehicles to be used in robberies. Road accidents are also causing vengeful behavior. Vast differences in the income of national and expatriates on contract work cause resentment. In addition, the availability and effects of alcohol consumption appear central in urban crime rates. Obtaining alcoholic beverages is often the reason for burglarizing houses and stores. The difficulty of establishing credible criminal justice processing has been illustrated on a number of occasions when offenders standing trial were seized from courthouses and police stations and murdered. On one occasion a district court building was invaded by tribesmen dissatisfied with a magistrate's verdict. It appears that it will take several generations of organized urban life and persistent efforts by government and criminal justice officials to establish general patterns of peace and a modern system of dispute processing.