The global arms trade network 1950-2007

Using SIPRI data on all international transfers of major conventional weapons 1950-2007, we study the relationship between differences in polity and arms trade. To study whether states tend to trade arms within their political vicinity we estimate gravity models of the likelihood of trade at the bilateral level and study the evolution of the global network over time. We find a stable negative relationship between differences in polity and the likelihood of arms trade for the duration of the Cold War, but not in recent years. In line with these results, the global arms trade network changes drastically over the sample period in several respects: it grows more dense, clustered and decentralized over time. The differences between the NATO and Warsaw Pact sub-networks that we find corroborate the common perception that the Warsaw Pact was more strongly centralized around the USSR than NATO around the UK, the US and France.