Did they ever really explain what happened between Mad Max and Mad Max 2, or were we just supposed to understand that there was a nuclear war?
It was made very clear there was a nuclear war over the world's dwindling oil supplies through the trilogy, but it was never made clear specifically when it happened. It could have even been before or during the first Mad Max. There is a lot of dialogue in the first Mad Max that suggests a severe gasoline shortage and a need to conserve fuel. Even a scene where Toecutter's gang steals fuel from a tanker truck. Mad Max 2(The Roadwarrior) mentions in their introduction what amounts to WW3 and how nations fought each other until the wells ran dry. The Beyond Thunderdome mentions that the war was nuclear.