Socialism

The USSR never had a single year of peace, in its entire existence. Following the revolution was a brutal civil war in which 14+ nations (including the US) landed troops to try to stop the republic. Even after the reds won against the whites, they had years of intrigues against them, then rising fascism, which a lot of historians see as a continuous conflict in eastern europe from the years between the twe world wars.

Stalin presciently stated that "we have 10 years to industrialize in the time it took capitalist nations 50+ years, or we're toast". Then you have operation barbarossa and the nazi onslaught, with its scorched earth policy and genocidal onslaught of the USSR, the eastern front of ww2 being the bloodiest conflict in history, with the soviets saving the world from fascism.

Then you have the US atom bombing civilians as a warning to the soviets, and 60 years of a cold war arms race, and too many other threats and incursions to count.

The USSR wouldn't have lasted a single year if they disarmed and followed that advice, and europe would probably be all speaking german now if it weren't for Stalin.