Intelligence agencies inflate threats.  Having domestic intelligence agencies creates suspicion and fear, and ultimately resentment. Domestic intelligence agencies are created in response to war and external threats, for example MI5 was created in the build up to world war one, and Australia’s intelligence service was created in response to the discovery of a soviet spy ring within the Australian government. [1] Having any such service involved in more than simply counter-intelligence against foreign services shows that the government does not trust its own people. The United States has until very recently not had a domestic intelligence exactly because it was considered that the FBI could do everything that was required without creating undue suspicion. Bureaucracies inflate threats so as to gain more resources, MI5 is a good example, it was given more resources than it needed to engage in counterintelligence against Germany so expanded its role to surveillance of elements such as pacifists and organised labour. [2] More recently the head of MI5 announced there were 1600 Britons plotting terror, which may simply be threat inflation, something which not only makes everyone fearful for no reason. [3] An agency which is equally focused on criminal investigation would have much less reason to inflate dangers in order to maintain or increase funding.  [1] Jackson, Brian a. ed., ‘Considering the Creation of a Domestic Intelligence Agency in the United States’, Rand, 2009,  p.15  [2] Wikipedia, ‘MI5’,   [3] Kayyem, Juliette, and Posner, Richard A., ‘Does the United States Need a Domestic Intelligence Agency?’ CFR, 17 November 2006,