You know, seeing the fact Ham Burger is a King, and obviously a caricature of the United States has got me thinking: Are monarchies the only forms of government in the One Piece world, or at least the vast majority? Does anyone even consider the alternatives, like representational democracy, or even direct democracy? Obviously Oda could have easily made Ham Burger President of Ballywood, but I think he's trying to allude to something bigger down the line, and even one of the main themes of One Piece: the nature of freedom, what exactly is it, and how it's represented by the individual and the masses.
Now, what kinds of government better represent the concept of freedom? Democracy, of course, is one of the more freer forms of government. As opposed to, say, a monarchy, or a dictatorship, where the power is handed down to a singular person, or a group of individuals, democracy is unique in that its power comes from the masses themselves. Theoretically, no one person should have relative power over anyone else. We're all equal, etc. We've seen this countless times, in the thoughts and actions of various characters in One Piece, from Luffy and raison d'etre of becoming Pirate King to have the most freedom, yet treating everyone else on the same playing field as himself, to the Revolutionary Army taking control of the power the Celestial Dragons have and giving it back to the people, to even just the citizens of places like the Mink Tribe, or Dressrosa. Ultimately, there is a universal equivalent to everyone on some level, and, no matter the background, race, creed, religion, gender, or social standing, we are all created equal. In the immortal words of Winston Churchill, "Democracy is the worst form of government… except for all the other forms that have been tried from time to time".
Now, for future implications: the fact that the Revolutionary Army is trying to take out the Celestial Dragons as opposed to the World Government as a whole implies that the system itself has some merit, but the negatives assigned to it need to be trim, beaten down and reworked from the ground up in order to create a fairer, stabler, longer lasting government. Now, I think, way, WAY farther down the line, when Luffy and Co. find the One Piece, they're going to unearth something MASSIVE that redistributes the power structure and makes the RA's plans more fruitful. How, exactly, I have no idea, but hopefully we'll get some answers to that in the upcoming chapters.
On a side note, this is why I love One Piece. The fact that I get to talk about geopolitical theory in a Japanese comic whose targeted demographic is TEENAGE BOYS amuses me to no end and is one of the reasons why this series is a cut above a lot of other series, not just in Japan, but the world over. Oda clearly is a master in his craft, and his world building is seriously top notch!