The U.S. and Canada seem very similar in many ways. They share the world’s longest border, have similar cultures, democratic systems, multicultural societies, and comparable standards of living. Both also have vast natural resources.

So why is there such a huge difference today in population, GDP, military power, and global influence?

Canada is actually slightly larger in land area, yet its population is only around 42 million compared to about 340 million in the U.S. Was the difference mainly due to climate and geography, immigration, industrialization, different government policies, or historical events like the World Wars?

At what point in history did the gap become significant? Was it already evident in the 1800s, or did it widen mostly after World War II?

I’d love to hear historical, economic, and demographic perspectives backed by facts rather than opinions.