Nazi troops flood over the Austrian border with tanks and artillery. Nazi sleeper cells and sympathizers arm themselves and begin patrolling the streets, crushing any attempt at resistance.
A “referendum” is forced on the country - stay independent, or allow itself to be annexed by the foreign power that now has every citizen and every cultural landmark held at gunpoint.
Because that’s exactly what happened in Crimea. The takeover of Crimea by Russia was achieved through extortion and illegal military occupation.
Just because a territory was historically under the rule of your predecessor doesn’t mean it’s your right to invade a neutral country and retake that territory. By that logic, Russia may as well belong to Mongolia because it was once conquered by the Golden Horde.
Soviet soldiers sit on the throne of the Last Chinese Emperor, Pu Yi. September 1945
Pu Yi, the last Emperor of China.
Aged 19 in 1924, with China in turmoil, he escaped to the international settlement at Tientsin to take shelter in the welcoming arms of the Japanese. They found a use for him and, when they took control of Manchuria in 1931, they proclaimed Pu Yi as Emperor of Manchukuo.