That would be small compared to dealing with the mindset of N.Koreans who are so completely brainwashed.....one does wonder though if 'some' might just not have swallowed the nonsense and just waiting for the leadership change to oppose them.....
The problem is communication is so very dangerous as family memebers watch each other as much as the police do. There is little if any trust elements possible.
And how about the Germans after WWII? It took seven years for the US forces to get rid of the Nazi sympathizers who were committing acts of guerrilla warfare them. Plus the country had been obliterated by the bombing during the war.