The Inter-Stellar Defense Treaty Alliance, also known as the ISDTA, is a faction made up of nations, dedicated to their mutual survival, peaceful coexistence, and independence outside of the Centauri Confederacy and the Earth Federation. The nation of Song-Tseng is a leading member of the Alliance.
The ISDTA contains over twenty-three independent states of varying size, power, and population, with a total population of just over one-fourth of the Earth Federation. The ISDTA does not regulate any matters of state in it's members, instead its concerned only with making absolutely sure that the Alliance presents a united front against the Confederacy and the Federation, and ensures all nations' militaries are coordinated, cooperative, and up-to-par.
The ISDTA is run by the Defense Council, in which each nation-state is given a number of votes based on their billions of population, with the default being one. The Overcouncil consists of the five most powerful and populous nations in the ISDTA, led by Song-Tseng, and dictates matters of overall policy. The Overcouncil is the true body of power in the ISDTA, due to the invaluable support each member provides, but the ruling nations have an infamously difficult time getting along with each other in times of peace. Non-Overcouncil members are primarily called upon to vote on issues proposed by the Overcouncil and have little way to check the power of a unified Overcouncil.
Under the ISDTA, each nation must make available at least 20% of their military forces to the ISDTA at any time they are needed, and 50% during a time of war. As well as these requestable forces, the ISDTA has a standing military contributed by the Overcouncil nations. All military forces in the ISDTA have a generally recognized set of standardized weaponry, vehicles, callsigns, orders, and chain of command, to allow for easier integration and defense.
The goal of the ISDTA is to make the Alliance too costly for either side to take safely. While the ISDTA could not hope to have any chance fighting the Federation or the Confederacy on it's own, it does not have to. Instead, it's strategy is to make the most out of their comparitvely meager forces, such that neither side can safely invade them without ignoring their rival, resulting in certain defeat.
One of the Alliance's primary problems is their lack of military technology and quality equipment when compared to the titanic behemoths of the Confederacy and Federation. The ISDTA simply does not have the money to properly equip it's forces anywhere near the level of the galactic superpowers, nor on such a scale. As such, its primary concentration is on equipment with maximum value per credit. The result is a truly anarchronistic military, which uses weapons considered long outdated alongside modern fleets and tactics. The Frame, the weapon of choice in the galaxy, is simply too expensive to be practically deployed by the Alliance in large numbers, so instead their forces consist largely of tanks, gunships, fighters, and other relatively ancient weapons. What little modern equipment they possess consists of scavenged and purchased surplus from both the Federation and the Centauri, resulting in an interesting hodgepodge of Frames and technology. This surplus is reverse-engineered to fuel their technological progress and upgraded to provide their elite forces.
The main focus of the Alliance is, of course, on the defense of the member states. As such, all ISDTA troops and installations are dedicated towards fortifcation. The most famous is the mind-bogglingly large and expensive "Eternal Line"(or "Etheral Line" as it is often mockingly referred), a multi-layer fortified barrier that spans the Alliance's borders with both superpowers. It is a gridlocked lattice of space-stations, military bases, fortified planets, and Flow-diverters, surpassed only by the Eden Line and Sol Sphere. The massive project is believed to have driven the Alliance deep into debt, time will tell whether or not if it was an effective investment. Despite the lower tech-level of the equipment, the sheer scale of the line ensures that it would take significant forces to crack the ISDTA's shell.