The union leadership is aware of the mentality of most of their membership - sheep - and thus, the bosses are able to put anything and everything over on them, up to and including losing their jobs to plant closures.
Not true. When my husband and I worked for Boeing here in Wichita (now Spirit) we were union members. Most of our friends and co-workers surprisingly supported the union (KS is a right-to-work state) but voted Republican. But hey, this is Kansas.