On April 16 in the fateful year of 1917, the Russian communist Vladimir Lenin arrived in Petrograd (now St. Petersburg) from exile in Switzerland. The Germans, with whom Russia had been at war since the summer of 1914, secretly arranged his return, granted him safe passage through Germany, and even gave him millions in gold. They hoped he would stir up enough trouble that Russia would withdraw from World War I. A vaccine is supposed to inoculate a person against a virus. Injecting Russia with Lenin was tantamount to administering the virus itself. British historian Edward Crankshaw noted that Germany saw “in this obscure fanatic one more bacillus to let loose in tottering and exhausted Russia to spread infection.” Within six months, Lenin engineered the October Revolution. His new regime made peace with Germany in March 1918. So, the Germans got their wish for the near term, but it availed them …