In an economic sense defence expenditure is normally exogenously determined, that is economic forces do not play the leading role in determining the level of defense expenditure. Adam Smith, in his writing An Inquiry Into the Nature and Causes of the Wealth of Nations states that "It is only by...

I show that in a conventional Ramsey model, between one-fourth and one- half of income differences across countries can be explained by a single factor: The steady-state effect of large, persistent differences in national average IQ on worker productivity. These differences in cognitive...