Yahoo! News Message Boards Top Stories: " The more intensive the US presence, the greater the problem. Members of the US Defense Science Board underscored just this in a 1997 report: 'Historical data show a strong correlation between US involvement in international situations and an increase in terrorist attacks against the US. In addition, the military asymmetry that denies nation-states the ability to engage in overt attacks against the US drives the use of transnational actors [terrorist from one country attacking in another]'

Source: Blowback: The Costs and Consequences of American Empire
by Chalmers Johnson -- pg. 9. "