Decentralization and population geography
Some great maps showing how a few densely populated parts of the US have nearly the same population as the rest of country.
This is why I favor highly decentralized governments like the EU: easy movement, centralized things that make life easier like ability to transfer between banks or no-roaming fees on phones, without forcing smaller countries to become exactly like the larger ones.
Poland or Malta might be more conservative on a lot of social issues than the Netherlands, but that’s their choice.