With increasing sophistication, economists have been estimating gravity equations for five decades. Robust evidence shows that borders and distance impede trade by much more than tariffs or transports costs can explain. We therefore advocate investigation of other sources of resistance, despite...

Existing theories of pre-emptive war typically predict that the leading country may choose to launch a war on a follower who is catching up, since the follower cannot credibly commit to not use their increased power in the future. But it was Japan who launched a war against the West in 1941, not...