The
galaxy-spanning
republic of
Dan Simmons's
Hyperion and
The Fall of Hyperion. Founded shortly after the
Hegira of humankind from the
dying Earth, the
Hegemony unifies hundreds of inhabited
planets -- from
Tau Ceti Center to
Renaissance Vector to
Maui-Covenant -- into one
nation, under one law and power.
The legislative authority of the Hegemony vests in two houses: the Senate and the All Thing. Senators are delegates of individual planetary governments. The dissonant All Thing, in contrast, is composed of interest groups and factions brought together through the datasphere communications network.
The executive power of the Hegemony vests in the CEO, who manages both the civil authority and the military. The power of the CEO is not clearly limited, but s/he is subject to instantaneous vote of confidence by the All Thing. The CEO is commander-in-chief of FORCE, the Hegemony combined armed forces. At the time of Hyperion, the CEO is Meina Gladstone, a former senator.
The territory of the Hegemony, known as the Web of Worlds, is bound together by the farcaster network, a system of instantaneous transportation. Thus, no planetary senator is ever far from his home constituency -- nor is FORCE far from any potential danger zone.
There have been but few cases of serious internal unrest within the Hegemony in its centuries-long history. By far the worst was the rebellion of General Horace Glennon-Height, which sought to overthrow the Hegemony and replace it with a dictatorship. Other matters of unrest have included ecological and cultural protection, as on Maui-Covenant and Qom-Riyadh.
In the eyes of the Hegemony government and its people alike, the chief enemies of peace in the Web are the Ousters, interstellar barbarians who raid civilized worlds -- and the chief allies of the Hegemony are the mysterious AI entities of the TechnoCore.