Contrast the sale of a car to the sale of a bomb: in the first case, both parties are clearly better off. In the second case, some people would argue that the c

Contrast the sale of a car to the sale of a bomb: in the first case, both parties are clearly better off. In the second case, some people would argue that the commons is better off by funding a public good (national defense). If the sold weaponry is not increasing security for the public, or even decreasing it, wealth is destroyed. It's like buying a car and burning it on the spot.