THE POLITICAL HISTORY OF SOUTH AMERICA COULD ALMOST be written in terms of military coups and returns to barracks. In Argentina, to take only the period since the Second world War, the military has relinquished power in 1946,1958, 1963, 1973 and 1983 (launching coups in 1955,1962,1966 and 1976). The military in Brazil, although less hyperactive than in Argentina, has relinquished power to civilians in 1945, 1955 and, incompletely so far, since 1982, while taking over government in 1954 and 1964. It seems therefore – rather paradoxically for some earlier writers on comparative politics (as was noted in the introduction) – that it is possible to speak of a military-civilian political system operating in much of South America. This features periods of military as well as civilian rule and operates largely because of a high degree of military self-confidence and the willingness of many civilians to contemplate military rule, even over a long period, with equanimity. A mere military coup, or return to barracks, need not imply a change in the political system itself. This point is not tautologous; the politica system may undergo genuine change, but only if civilian attitudes to the military (and willingness to accept military intervention) and military attitudes to civilian politics chan e fundamentally. Is there any sign that this has happened or is about to happen in the cases of Brazil and Argentina?