First, quite different empirical results can be obtained depending on which measure of military expenditure is used in this analysis. A consistent dynamic system is used to provide a framework to analyse the differences between the relationships explaining four measures of military expenditures. Second, there are three changes in strategic posture : withdrawal from the colonies after some expensive colonial wars, decision to acquire an independent nuclear capability and the withdrawal from NATO's integrated military commande in 1966. We examine the impact of each on the different measures.