he drawing to an end of World War I in autumn 1918 only intensified the deepening conflict in industrial relations in Canada. Workers escalated demands for the universal eight-hour day, union recognition, and better wages. The number of strikes and workers involved in them continued to escalate:

1916 168 strikes 26,971 strikers
1917 222 strikes 50,327 strikers
1918 305 strikes 82,573 strikers
1919 428 strikes 149,309 strikers
1920 459 strikes 76,624 strikers

In 1919, when almost 150,000 Canadians went on strike, the country lost in production the equivalent of over 3.4 million striker days. The breaking down of barriers between craft and other workers begun during the war continued into 1919. In fact, the more conservative craft unionists saw their influence eroding quickly. At the annual Trades and Labor Congress (TLC) conventions in 1917 and 1918, their policies encountered challenge after challenge from militant delegates demanding the TLC adopt industrial unionism and aggressively pursue radical politics based on the ideology of class struggle. While the TLC leadership withstood this challenge in its conventions, support for a more progressive programme could be found across Canada.

The pattern of this growing revolt varied somewhat across the country. In central Canada, militant and radical union activists tended to remain in their existing unions. Their strategy was to radicalize from the inside by converting to industrial unions. In the West, union activists led a movement to create a radical alternative to the TLC. On 13 March 1919, a special convention was called for this purpose. Delegates from across the region gathered in Calgary at the Western Labour Conference where they formulated plans to form the One Big Union (OBU). In a referendum following the Calgary meeting, thousands of workers, mostly in western Canada, voted overwhelmingly to secede from the TLC. In June, they formally launched the OBU.

The OBU declared itself a revolutionary industrial union, advocated the use of the general strike, and declared its support for the Bolshevik Revolution in Russia. More immediate OBU objectives included: union recognition; the six-hour day/five day week to help alleviate unemployment; better wages; and the "repeal of Orders-In-Council restraining the liberties of workers." Because the OBU was in its formative stage in spring 1919, it did not play a direct role in the strike wave rolling across the country. However, the concept or idea of a "one big union" became a symbol during this tumultuous period, and many of the leaders of this revolt were prominent OBU advocates.

The appeal of a "one big union" also influenced workers in the Maritimes. While unionists in the West were busy planning the One Big Union, workers in Amherst, Nova Scotia created their own independent One Big Union. Indeed, before the official launching of the OBU in the West, the Amherst OBU led a general strike against all the town's employers. The Amherst strike and many other local confrontations occurring across Canada during this spring of labour's discontent were abruptly pushed from the front pages of the country's newspapers by the even more dramatic events developing in Winnipeg.