INTRODUCTION

Since the pioneering works of Anthony Downs (1957), James Buchanan and Gordon Tullock (1962), and William Riker (1962) most of the public choice literature have been developed under a democratic framework. These works, which are based upon the assumptions of utility maximization and rationality of the individual voters, present testable theories of political behavior. Unfortunately, democracy, while highly desirable, does not represent an appropriate description of the political regimes that have ruled most countries in the world during a large part of this century. Zehra Fatma Arat (1984) has built an index of democraticness for 2 selected countries which allows me to clearly illustrate this point. From the Arat sample I have 3 selected the 63 countries which have been included during the whole period and I have classified 17 of them under the label of "first world countries", and the remaining 46 under the label of "others"; from the later I have selected the 19 Latin American countries (see 2 Appendix, Table 1). While the average score for the 17 "first world countries" reached 19.40, it dropped for the 19 Latin American countries to 10.19, and to only 8.04 for the 46 "non first world countries" as a whole. From these scores it comes clear that, during this historical period, democracy, 4 rather than be characterized as the rule, has to be considered as an exception! The first paper in the public choice literature developed under a non-democratic framework was presented by Thomas Ireland in 1967. This work, as well as the Gordon Tullock's (1971) paper, opened a new framework to the study of non-democratic changes of government. Until Ireland's and Tullock's works, the study of revolutions was an exclusive field of political scientists, who focus their interest on the public good aspect of the revolutions.5 Since the appearance of Ireland's and Tullock's works a group of scholars (Leites and Wolf, 1970; Tullock, 1974; Silver, 1974; Cao Garcia, 1983; Cartwright, Delorme and Wood, 1985; etc.) have challenged this romantic notion of revolution using the assumptions and methodology provided by the economic theory. The by-product designation of this self 6 interest theory is credited to Gordon Tullock (1971), who used the term following Mancur Olson (1965), whose analysis of the motivations of an agent as an active participant in a collective action can be extended to the revolutionary activity. While most of the public choice literature in non-democratic changes of government center their interest in the so called "mass revolutions" (Ireland, 1967; Leites and Wolf, 1970; Tullock, 1971; Cartwright, Delorme and Wood, 1985; Kuran, 1989; Grossman, 1991; etc.), most of the actual irregular executive transfers are military coups d'etat. For example, mass revolutions like the French Revolution of 1789, the Russian Revolution of February 1917, or 3 the Iranian Revolution of 1978-1979, are completely unusual events in Latin American countries; instead, military coups d'etat are a well known political tradition. To the best of my knowledge, only Gordon Tullock (1974), Silver (1974), Cao Garcia (1983), and Mbaku and Paul (1989) analyze coups d'etat. Of these scholars, only Gordon Tullock's illuminating work explicitly studies military coups d'etat by means of a microeconomic analysis of benefits and costs. Tullock differentiates coups d'etat from mass revolutions and analyzes structural factors that affect the participation of the army officers in the coup. But, is point of fact, as Tullock (1987) emphasizes, that much more progress has been done in understanding democracies than dictatorships; this paper is intended to contribute to fill this gap by proposing a simple theory which may help us to better understand military coups d'etat. I will devote the following section to develop the theory. It will closely follow the Tullock's approach to the subject but it will also take into account the civilian side of the coup; the inclusion of civilian considerations constitute the basic difference between my framework and that of Tullock, and radically departs from the by-product theory of revolutions since it provides public good considerations, instead of private interest rewards, as the engine for the motivations of the civilian actors. These considerations are a side product of the pressure groups approach to the economic policy developed since the seminal work of Arthur Bentley (1908). To take into account the role played by civilian groups will allow me to obtain further insights into the causes of military coups d'etat; insights which are unattainable if we consider solely the military side of the coup.