Through the 1980s and into the 1990s union membership, as a share of the Australian workforce, has been falling. In the space of two decades from 1976 to 1996, union density (the proportion of employees belonging to a union) dropped by two-fifths. The union movement, in a country which had once enjoyed the highest density in the world, is facing a crisis of membership.

While union density is not the same as union strength, it is nonetheless one of the most important factors that affects a union movement's power. From overseas experience, particularly that of the United States, it appears that declining union density may raise major problems of legitimacy for the union movement as a whole. It can be used as a weapon by employer groups and others to argue that the ‘privileges’ afforded unions, and denied the majority of the workforce, should be withdrawn. Declining union membership may lead to cutbacks in staff and resources in unions and thereby to reductions in the union organising effort and in services provided to members. Success (or failure) in recruiting union members may influence the attitudes and actions of employees and employers and encourage success (or failure) elsewhere (Rose & Chaison 1992; O'Neill 1971; Western 1993b).

Whether the syndrome of self-perpetuating, deep decline evident in the United States will be repeated in Australia is difficult to predict, but it highlights the importance of understanding the reasons for union decline and the factors that work to reverse this trend.