Final answer:
The type of union security that is most prevalent in union contracts is the union shop. Union shops are common measures within labor agreements, making it a requirement for new employees to enroll as members of the union after a certain period of employment.
Step-by-step explanation:
The type of union security that accounts for almost three-fourths of union contracts is the union shop. A union shop agreement requires new hires to join the union within a certain period of their employment and remain members as a condition of employment. This is different from a closed shop, which requires union membership before employment, and an agency shop, where employees don’t have to join but must still pay dues. Maintenance of membership clauses simply require workers to stay in the union for a certain period if they voluntarily join.
It’s important to understand that union security clauses are deeply intertwined with the history of labor in the United States. Labor unions were established to help improve working conditions, wages, and job security for workers, particularly in the manufacturing sector. However, as the economy has shifted towards services, union membership has steadily declined. This drop in membership can be partially attributed to the fact that unions have had more difficulty organizing in service sectors compared to manufacturing.