At 6:00 A.M., June 1, 1916, some 10,000 longshoremen up and down the Pacific Coast struck to enforce the new wage scale and working conditions established by the recently concluded convention of the ILA's Pacific Coast District. If employers resisted the demands, put up a fight, or sought a local settlement or local negotiations, the port unions were instructed to refer them to the district executive board. It alone was empowered to settle the strike.

This, the first coastwide strike of longshoremen, had been building almost from the turn of the century. Unionism had come early to the other Pacific Coast ports: Longshoremen in Portland formed a "Protective Union" in 1868. In the 1880s, Tacoma longshoremen organized a cooperative in an effort to restrict the labor force and limit the competition for jobs. In the last years of the old century, San Pedro began developing a spacious inner harbor and, soon after, longshoremen in San Pedro organized a union. In 1901 Seattle longshoremen joined the ILA. Local unions in the dozen or more ports in Oregon and Washington in 1908 formed the Longshoremen's Union of the Pacific in an unsuccessful effort to rescue a desperate strike. In 1909, recuperating from its disastrous loss, the coastwide union became District 38 of the ILA, with a sweeping grant of autonomy that played a key role in the strike twenty-five years later. Of the twenty-six unions on the coast, only the Riggers' and Stevedores' in San Francisco held out. Finally, in 1914, it, too, affiliated.