A small, mobile police force was chosen to reduce potential for tensions with the United States and First Nations. ... Macdonald's greatest fear was that if the Americans occupied the NWT that they would not leave and the region would be annexed to the United States
The North-West Mounted Police (NWMP) was a Canadian para-military police force, established in 1873, to maintain order in the new Canadian North-West Territories (NWT)
