The incidence and changing significance of terrorism has had some obvious effects. The most evident is the diversion of resources into internal security functions. Protecting political leaders, guarding vital locations, screening people at airports, and hardening targets all require increasing amounts of money, labour, and time. The most publically visible security precaution is the screening of passengers at airports. Apart from the time and inconvenience costs to the public, the financial costs of screening precautions have been enormous. One study estimated the costs of mandatory screening in the United States at $194.2 million for the period 1973–76, An analysis of the deterrent effects of screening showed that this was a cost of $3.24 million to $9.25 million expenditure to deter a single hijacking.

There has been a rapid increase in internal security budgets, which shows no sign of abating, and the private security industry is increasingly involving itself in internal security-type operations. This latter trend is particularly worrying in view of the competitive nature of the private security industry and its lack of public accountability. Jenkins sees this as part of