The greatest pall to hang over the world was the Cold War..
Not for the Russians it wasn't. It's important to note that as far as the Soviets were concerned, the United States posed a far less existential threat than Nazi Germany or even China, the former of which cost them $20 million lives and sacked several of their major cities.
The Americans went through the Cold War with this concept of "Mutually Assured Destruction," the assumption that the Russians could be convinced not to attack the United States because any attempt to do so would cause the total end of their civilization. The Russians never really got that concept; THEIR idea of nuclear war was "Nuke em till they stop shooting back." IOW, in their view getting nuked by the United States was hardly the end of the world; in some ways, it was no worse than what the Nazis did to them decades earlier, except that this time the Russian counterattack would immediately inflict identical damage to the United States and give them time to rebuild.