From the 1940s to around 1980, American politics was about as centrist and bipartisan as it has ever been. One reason is that, during and prior to this period, the country faced a series of common challenges and enemies, including the Great Depression, the Axis Powers during World War II, and the Soviets during the Cold War. Given the psychology of tribalism that we described in chapter 3, the loss of a common enemy after the collapse of the Soviet Union can be expected to lead to more intratribal conflict.
