I just came up with a theory about Phoenix Wright. Basically, the game takes place in an alternate post-WWII Japan where the US never developed the Manhattan Project, and therefore never nuked Japan. Instead, Japan was steadily subdued with sustained conventional bombing of its major cities that went on for years, before troops were eventually sent in. By this point, every major Japanese city was reduced to almost nothing, the imperialist government has long since ceased to function on even the most basic level and only the tiniest fraction of their former inhabitants not dead or fled, though rural areas were relatively untouched. Without even the remnants of a functional state and industrialised economy, and the US wanting a strong and capable ally and platform in Northern Asia in the inevitable conflict with the USSR, Japan was annexed directly, and massive amounts of resources were directed not only to rebuilding their shattered economy, but also to encouraging American families to relocate to Japan in order to restore their urban population.
By the mid 2000's, we see the results of these efforts to rebuild the country in America's image. Large, highly Americanised cities with an overwhelming majority of Caucasian inhabitants with a strong American cultural identity, though a significant Japanese influence can still be seen if one knows where to look, with the surrounding countryside still inhabited with an ethnic Japanese majority who, though they retain a good deal more of their original culture than their urban counterparts, have nonetheless been every heavily Americanised over the past half century.