The terminology Law Enforcement Agency in mainly used in the North America area of the world. Whilst a Law Enforcement Agency is linked to the European aspect of Policing in real terms it covers a broader span of Law Enforcement Agencies and areas of jurisdiction than that encompassed by the terminology of Policing. Law Enforcement Agencies tend to act within a national and international jurisdiction whilst a Police Service tends to work within smaller areas of jurisdiction.
The Wikipedia describes a Law enforcement agency (LEA) as a term used to describe either an organization that enforces the laws of one or more governing bodies, or an organization that actively and directly assists in the enforcement of laws. In doing so, the LEA assists the governing bodies to provide governance for their subjects.
Typically a LEA is established and constituted by the governing body it is supporting, and the personnel making up the LEA are from the governing body’s subjects, for example the Australian Federal Police is established and constituted by virtue of the Australian Federal Police Act 1979 .By Definition, federal LEAs can only be established by the governing body of the relevant federation. Divisional and sub divisional LEAs can only be established by their relevant governing bodies, and national LEAs can only be established by the national governing body of a country.
For reasons of either logistical efficiency or policy, some divisions with a country will not establish their own LEAs but will instead make arrangements with another LEA, typically from the same country, to provide law enforcement within the division. For example, the Royal Canadian Mounted Police (RCMP) is a federal agency and is contracted by most of Canada’s provinces and many municipalities to police those divisions, even though law enforcement in Canada is constitutionally a divisional responsibility. This arrangement has been achieved by formal agreement between those divisions and the RCMP and reduces the number of agencies policing the same geographical area. Similarly, the Australian Federal Police AFP) is a federal agency and is the contracted police agency for the Australian Capital Territory and Norfolk Island.
In circumstances where a country or division within a country is not able to establish stable or effective LEAs, typically police agencies, the country might invite other countries to provide personnel, experience, and organizational structure to constitute a LEA, for example the Regional Assistance Mission to the Solomon Islands which has a Participating Police Force working in conjunction with the Solomon Islands Police Force, or where the United Nations is already providing an administrative support capability within the country, the United Nations may directly establish and constitute a LEA on behalf of the country, for example for Timor-Leste from 1999 to 2002.