In the previous post, we defined a "Continental" country as one having btoh 100 million or more people, and over 1 milion square miles. Here are some that didn't quite qualify (and what they might have done to qualify).
European countries. No single European country except Russia is "continental" in either size or population. A united (non-Russian) Europe would qualify, however.
Mexico. It has just over 100 people but only three-quarters of a millions square miles of land. If it had kept Texas, California, and everyithing in between, it would be a Continental power (as well as being stronger than it is today).
Canada: the inverse of Mexico. More than enough land, not nearly enough (30 million) people. As one country, Canada-Mexico would qualify.
Japan: Certainly enough people, not enough land, which is why they tried to conquer some in the early part of the 20th century. With Korea, Formosa (Taiwan) and Manchuria (originally a no-man's land, now part of China), Japan would have a critical (land) mass.
Indonesia: A quarter million people, less than three quarter of a million square miles. Again, too many people on too little land. And it doesn't have Japan's advantages of advanced education and an industrial economy.
Australia, the Eastern Hemisphere's "Canada." Again, Indonesia-Australia would qualify.