The rebellion in Russia by Wagner mercenaries confronted Western officials with one of their gravest fears: the possibility of political chaos and instability in the country with the world's largest nuclear arsenal.
Anxiety over who might gain control of Russia's weapons of mass destruction has long tempered Western hopes that President Vladimir Putin might be ousted from power. But months of nuclear posturing by Putin and other senior Russian officials, and a new debate among Moscow analysts on using a nuclear weapon on a NATO country, have raised doubts about whether Putin really provides the stability necessary to avoid an atomic Armageddon - or if he is the risk they should fear most.