In the aftermath of the 1901 teamsters' and waterfront strike, Teamsters, Local 85, had been nailed down by a contract clause that read: "The Brotherhood of Teamsters and Auto Truckmen are not in favor of sympathy strikes and will do everything they can to avoid them." That clause was much in the minds of the leaders of the Industrial Association, the longshoremen, and Mike Casey, longtime president of Local 85 and a veteran of the 1901 strike, as teamsters prepared to take action on the 1934 strike. The question was set for a special meeting Sunday, May 13.

The longshoremen's strike committee sent its own representatives to make sure that the teamsters knew of its willingness to negotiate wages and hours, as well as its insistence on the closed shop. Casey and his associates asked the teamsters for a declaration that they would haul cargo to and from the pierheads, but would not enter the docks. The members rejected their proposal; instead, they shouted approval of a resolution "not to transport merchandise to or from the docks." It was not, Casey emphasized to the Chronicle afterward, a "sympathetic strike," but "a definite boycott of the waterfront." He explained, "our action was taken for protection of the men. If we continued to haul cargoes to the pierheads, our men might become involved in fights and injuries might result." 22 After the meeting, a number of union drivers joined the longshoremen in a picket parade along the Embarcadero. Eliel called it "a definite vote of sympathy in support of the strikers" by a "substantial number" of teamsters. Oakland teamsters took similar action the next day, and the Seattle teamsters on May 15. When Los Angeles teamsters voted to refuse to haul cargoes to and from the harbor areas, vehicles were put under police protection. An ILA statement exulted: "With the Teamsters behind us we've got them licked. We are sitting on top of the world. There are 2500 freight cars sidetracked between San Francisco and San Jose and they can't move until we give in." Southern Pacific reported the 388 cars held up were more than twice normal. 23