A cache of more than a dozen letters, diplomatic notes, bills of sale, and export passports suggests this may have been a key reason for Armenia’s decision to withdraw from the CSTO, undermining the authority of Russian dictator Vladimir Putin among former Soviet republics. Theoretically, CSTO members are obligated to defend one another in case of an attack. Azerbaijan exited the bloc in 1999. Read also: NATO faces serious challenge with potential Putin-Lukashenko plans for Baltic unrest Belarus actively aided Azerbaijan’s armed forces between 2018 and 2022, as tensions peaked with Armenia. Th…