Oh, the Republic of Ezo guys? I guess it could be seen that way, but voting was limited to men of the samurai class and the reason they could take a large chunk of Hokkaido was that it was populated by Ainu people who they killed and displaced in large numbers. I would consider that more a colonial expansion than actual democracy, even though it was more democratic than any previous form of government in Japan. Most shinsengumi-related media is...very romanticised.