To quote myself:
Vietnam’s quarantine, I imagine, was much facilitated by the people’s apprehension of threats and dangers coming from the north.
That is, from China. Back in 1979, China invaded Vietnam, devastated the borderlands and withdrew in the face of fierce Vietnamese resistance. Soviet-Russian wisecrackers called it the First Socialist War.
The Patriotic War of 1812 was Russia’s war against Napoleon’s army, which invaded Russia in June and was driven out in November. The Great Patriotic War is the standard Soviet name for the Russian-German war of 1941-45. Occasionally, WWI had been called the Second Patriotic War before the Bolsheviks took over the country. Under Communist rule, WWI was re-dubbed the First Imperialist War. That was probably the immediate source of the “First Socialist War.”
This first socialist war commenced at dawn on 17 February 1979, when two hundred thousand Chinese troops crossed the Vietnamese border.
Two hundred thousand troops. That’s a lot for a “punitive action” (for kicking China’s bloody puppet out of Cambodia). For comparison, Wikipedia says the number of US troops in Iraq peaked at 170,000 in 2007.