Vladimir Putin already has bases and soldiers in Alexander Lukashenko’s country. Photo by Maxim Malinovsky/AFP via Getty Images BERLIN – When the Soviet Union collapsed in 1991, nuclear weapons, control of which was transferred to the new Russian Federation, were stationed in three countries suddenly independent of Moscow. By the mid-1990s Ukraine, Kazakhstan and Belarus had transferred the nuclear weapons back to Russia. On 25 March this year Vladimir Putin, the Russian president, announced that he intended to station “tactical” nuclear weapons in Belarus, which would thus be the first time in over 25 years that Russian nuclear weapons have...