Because the First Special Service Force was a joint project within an overall framework of the Allied war effort. In fact, the initial plans called for raising a multinational commando force of Canadians, Americans, and Norwegians. The last dropped out due to lack of numbers, but did supply instructors.
While it was in practice an American unit, the Devil's Brigade actually started as a British proposal. It originated from an ambitious British initiative for invading Norway called Operation Plough, a brainchild of the eccentric inventor Geoffrey Pyke.
Early in 1942 Allied strategists were considering a highly novel scheme known as Operation "Plough" which had caught the imagination of both Mr. Churchill and Lord Louis Mountbatten. It envisioned operations with special vehiclees, sent in by air, to be conducted during the winter of 1942-43 in the snow-covered areas of Europe.
- Stacey, C. P. Official History of the Canadian Army in the Second World War. Ottawa: Queen's Printer, 1955.
Pyke's ideas won the support of Lord Louis Mountbatten, then head of British Combined Operations. However, he felt British resources were stretched too thin for such a project. Instead, Mountbatten offered the proposal to the American General George Marshall, and secured American commitment - despite poor reception by the Pentagon's analysts once Marshall brought the idea home.
It was also at Mountbatten's instigation, when he arrived in Washington D.C. later on 9 June, that Robert Frederick was given command of the unit. Operation Plough was now rapidly turning into a reality, so Mountbatten then took Frederick and Pike with him to enlist the Canadians.
Great Britain might not have the resources to participate, but the nature of the unit made the Dominion of Canada an obvious candidate for representing the British Commonwealth.
Mountbatten was now certain that Britain would not be able to assist Frederick with Plough in any substantial way; it just didn't have the resources. Plough needed partners, and Mountbatten decided that Canada could represent Britain and the Commonwealth in the unit ... Mountbatten knew that its soldiers were acquainted with snow and cold, and most - presumably - could ski.
- Nadler, John. A Perfect Hell: The True Story of the Black Devils, the Forefathers of the Special Forces. Presidio Press, 2007.
and an ideal representative in
Ultimately the operation was scrapped, and the created force was effectively an American military unit. Nonetheless, because the impetus for the unit's creation was British, it is unsurprising that Canadians - at the urging of the British leadership - would have signed on to the project.