In September 1917, United States Justice Department agents raided Wobbly offices across the nation with warrants branding the entire leadership (some 200 men and women) as subversives. The major trial took place in Chicago and, according to historian Joyce Kornbluh, "virtually the entire first and second tier of past and present leaders were sentenced to federal prison terms of from ten to twenty years..." (Kornbluh).
In the Pacific Northwest, with the leadership incarcerated, the IWW advised members to return to work but to continue to strike while on the job. Wobblies returned to loggers camps and sawmills that started up again with the same poor conditions and 10-hour day. IWW members worked very slowly, quit often, and in general succeeded in slowing and hampering production.
Later in the year, the U.S. War Department took over Northwest logging operations to cut the Sitka spruce that was essential to build airplanes needed to wage the war, and that grew only in the Pacific Northwest. The U.S. government joined cities, towns, and county sheriffs, backed by employers, in jailing IWW members and leaders, and in closing or wrecking IWW halls. At the same time, the government pressured firms to implement the eight-hour day and more sanitary conditions, and did so in government-run wartime logging camps.