The history of transnational trade unionism has been analysed in terms of mutual assistance, regulating global capital, augmenting the legitimacy, prestige and power of unions and their leaders, and providing avenues for states to prosecute national interests. From the 1920s to the 1980s, international organisations of trade unionists constituted a site of struggle between the antagonistic philosophies of transnationalism and trade unionism of Communists, social democrats and liberals, the USSR and the capitalist democracies.