The hiring and employment of union members only – called “closed shops” – are illegal under the Taft-Hartley Act. A “union shop” where every member of the bargaining unit must become a member of the union after a specified amount of time is legal. These jobs are treated the same as other jobs; such as, contractors must post these employment openings with the state employment service delivery system (ESDS). The contractor may want to include - as a job requirement - that the successful candidate must become a member of the union after a specified period of time.