Merchant of Death, Lord of War, the Bill Gates of Arms Dealing: Viktor Bout’s nicknames speak for themselves. The notorious arms dealer has been returned to “the motherland” – as Russia put it on Thursday – after a dramatic high-level prisoner exchange with WNBA star Brittney Griner. Russia’s persistent pursuit of Bout’s release was widely believed to have been motivated by his links to the country’s notorious military intelligence. Thursday’s prisoner exchange, which took place in Abu Dhabi, also sheds rare light on Vladimir Putin’s strategic priorities at a time of heightened tensions with the west over Ukraine. Much of...