The World Government is a political organization comprised of the majority of the World at large, ruled by the Gorosei. It was established 800 years ago. The Marines serve as their primary military organization, headed by the Fleet Admiral, while the Cipher Pol operate behind the scenes, either through sabotage, reconnaissance, spying, espionage and/or assassination; their most powerful enemies are largely pirates and revolutionaries. The Commander-in-Chief oversees both the Marines and Cipher Pol as well as the Shichibukai, at least officially, and is second only to the Gorosei. Impel Down serves as the World Government's maximum-security prison. Collectively serving as the most prominent antagonists in the series, the World Government is largely portrayed as a corrupt entity, particularly through the pitiless use of their Absolute Justice doctrine and the depravity of the aristocratic World Nobles.
About the World Government
The World Government is affiliated with roughly one hundred seventy countries from around the world. Those member countries retain autonomy, that is to say, the countries run their own internal affairs (though the World Government does sometimes meddle), but cooperate with the World Government for massive international relations. Their political ideals are unknown and everything they do is considered to be right. Not everyone approves of their political ideals, as there are people like Monkey D. Dragon who are against it. They approve of Absolute Justice and reside in the holy land of Mariejois, ruled by the Gorosei, the highest authority of the world. They are afraid of losing power and the World Government depends on the Three Great Powers to keep the world from falling apart.
At first glance, the World Government maintain a worldly order that benefits all, making the world safe for the sake of everyone. Using the Marines, they pursue criminals endangering the lives of those who are innocent, protecting the people of each country in the world. The World Government is the largest World Power maintaining full rights to halt or encourage any political action without question or opposition from any side.
The reality though is that, unknown to most citizens (and many world leaders), the World Government's actions are secretly, and often, based on corruption or questionable motives. Often when the story line involves them, it shows them hiding the truth or ignoring the rights of the people with many individuals using justice to further their own aims. Individuals who become the enemies of the World Government are viciously hunted down and dealt with and all those who walk along the same path as them are doomed to share the World Government's wrath.
The World Government's power to release information on anyone as they please can often lead to the truth being suppressed, altered or ignored all together. Any countries attempting to protect or harbor criminals are at risk from the World Government, although what would happen exactly has not been addressed yet. For the most part, the important role they have in maintaining world stability far outweighs the corruption they often display though this is changing as more people are beginning to question whether what the World Government is doing is right. They allied themselves with seven powerful pirates in exchange for pardoning their past felonies, but allowed them to continue committing crimes (though still to a certain extent) in order to maintain power and status.