"ers and Pipe Fitters, an AFL-CIO affiliated union, also backed Obama, bringing the total number of international unions who support him to 4 with about 4.5 million members.)The remaining members of CtW are the Laborer's and the Teamsters.According to a Laborers' International Union (LIUNA) press release put out today, that union of mainly construction workers is preparing its third member survey t" . . . .