(Thanks to Martyn Potts)

The Union of Xyon has a bi-cameral government with a 20 member High Council (Hakamim) and 134 member Parliament (Sanhedrin). The primary role of these two bodies is to work together to preserve the integrity of the Union against any possible external threat or internal dissention. The former is to be countered through appropriate defences and alliances, and the latter through promoting peace and prosperity throughout the Union whilst allowing a high degree of autonomy for member systems.

The Hakamim (pl) Hakam (sng) ("The Wise")

The leader of the Hakamim is called the Speaker who, along with 4 other senior members, forms the Quorum. At least one member of the Quorum is required to be present for the Hakamim to function.

The Speaker is chosen by the Hakamim from within its number. The way this has worked in practice is that the outgoing Speaker nominates his successor who is then approved by the rest of the members. The members of the Hakamim serve either for life, until they choose to retire or, in exceptional circumstances, are sacked by the Speaker. The Speaker can only sack one Hakam per year, and the majority must approve anyone brought into the Hakamim from outside. This acts as a check on the powers of the Speaker, not that a Speaker has ever tried to abuse those powers. The Speaker can only be removed by at least 3 Quorum members baked by 11 other members of the Hakamim. There has never been any cause to do this in the history of the Union.

Agama provide 3 members for the Hakamim with the other systems in Quadrant 0 providing 2 each. The remaining 7 members are selected from amongst the largest populations in the outer quadrants.

The Sanhedrin

The citizens of the systems within the Union directly elect their representatives to the Sanhedrin, with elections being held at least every 7 years. The number of seats a system has in the Sanhedrin is related to its population, but each system has at least 2 representatives. The representatives are constituency based, with the top two candidates in an election going through to a second ballot. If, for whatever reason, a seat becomes vacant, a bye-election will be held.

The Government

The Hakamim appoints a Prime Minister who in turn appoints a Cabinet to form a government. The Prime Minister and Cabinet members can be from either the Hakamim or Sanhedrin, but it has become customary for them all to be members of the Sanhedrin. Indeed, it has been over 200 years since a Hakam held a Cabinet post, and over 250 years since one held the Premiership.
The Cabinet posts, in order of precedence, are as follows:

Prime Minister
Commercial Secretary
Treasury Secretary
Secretary General of the Union
Secretary of Defence
Secretary of External Affairs
Secretary of Science and Research
Speaker of the Sanhedrin

Exercising Power

The Cabinet has Executive powers. So does the Hakamim, and occasionally it will use them. However, the Hakamim more usually confines itself to an advisory role. Any legislation has to be approved by both the Sanhedrin and the Hakamim, and both have the power to amend legislation.

In an Emergency, the Speaker of the Hakamim can rule by decree, provided he has the support of the Quorum.

Only the Speaker of the Hakamim has the power to dissolve the Sanhedrin and call an election outside of the constitutional requirement of at least once every 7 years.

Political Parties

Political parties in the Union come in 2 flavours: those with support across multiple systems, and those based in one system. The former have the most influence politically and the latter are mainly found in Quadrant 0.

The current coalition consists of 3 parties:

Maskalim - the second oldest party and the one that has done most to shape the Union over the past 300 years.
Labour - the oldest party, originally drawing the corps of its support from Belters.
Harikat Amal - founded on Akhenaton and drawing support mainly from the Outer Quadrants.

Colonial Government

Each planet/belt has a bi-cameral government: an elected Knesset with Executive and legislative powers, and an appointed assembly (Kahal). The appointees in the Kahal represent a wide variety of interest groups from business to labour, religions to education institutes, the military (must be retired) to legitimate free traders. There categorically are no pirates sitting in any Kahal.

There is also a Governor (Shaliach) appointed by the Hakamim.

The Kahal has to approve all legislation and has the power of amendment, but it cannot introduce legislation. In the event a deadlock between the Knesset and Kahal the Shaliach has the casting vote. In practice this rarely happens as the two normally will reach a compromise rather than see the Shaliach intervene.