Humanity is a relatively young civilization among the stellar nations. But ambitious and audacious as hell. Born in the little-studied sector of the Universe, mankind presented itself to the galactic community as a strong and self-sufficient nation with a powerful military force and balanced economy capable of affording a mighty stellar fleet.
Despite its name the human state is more a confederation than an empire. Colossal distances and lack of decent communication means make it impossible to maintain a strongly centralized power system. Formally, at the head of the state stands the Emperor who chooses his heir among the candidates proposed by the noble houses. The House of Lords then votes to approve the heir as the Crown Prince and Grand Duke of Mars. From this moment the prince loses all ties with the family. Refuses all other titles, standings and heritage. Since that moment the Empire is his life. Of course, this political system breeds rivalry between the noble dukes and the houses of the Empire.
Second to the Emperor are the Cabinet of Ministers and the House of Lords.
The House of Lords is the upper chamber of the parliament, which includes representatives from all planets of the Empire. The number of representatives depends on the population of the planet. Each star system has its own House of Representatives which deals with local affairs.
A separate stratum of the population is the nobility. Since maintaining and developing the army at space distances is a task of utmost difficulty, the Empire had to actually restore feudalism. Besides the standard institutions of society there are noblemen. This is a caste of professional warriors that are the first to answer the call, the first to blaze a trail. As the knight’s vow goes: “We are the shield of mankind that will protect peaceful life from dangers. We are the sword of mankind that will destroy any threat.” Each nobleman can choose from two ways of life. Abandon the title and live a normal life like all others. Or keep the title and get the knightly privileges with obligation to take up arms whenever the Empire calls, and be the force that stands in harm’s way.
Obviously, the presence of such a privileged population stratum creates social friction. But due to its wise and farsighted policy the Empire managed to defuse crisis situations so far. Most of them.