War has started again in the Caucasus, a region between the Black Sea and the Caspian Sea consisting of Armenia, Azerbaijan, Georgia, and parts of Southern Russia. It is a kind of mountainous border between Asia and Europe, in a region with vast oil resources that was conquered by Russia a few hundred years ago. The fighting that has erupted is over an enclave known as Nagorno-Karabakh, a remote territory without strategic value that is nevertheless, as writer Andrew Higgins conclud ...