ABSTRACT
THE INSTABILITY OF MOST LATIN AMERICAN COUNTRIES derives to a large extent from the difficulty of incorporating the working class and other popular strata into the political system. European countries also had to face a similar challenge decades ago, but the central position they had in the international economic system helped to ease the tensions. In the Third World or Latin America the problem is compounded because to the working class must be added large sectors of urban marginals, peasants and often the impoverished middle classes. These groups tend to form broadly-based parties which become the main contenders for power against the dominant establishment. They are placed in a somewhat similar position to that occupied by Labour, Social Democratic or Eurocommunist parties in Europe or Japan. But they are based on different organizational and ideological elements, and their popular rather than working-class nature often involves strange coalitions. Brazil and Argentina share fully these traits. In order to understand the characteristics of the popular political parties in those two countries one must examine them in a Latin American comparative perspective.
