The United Galactic Alliance is a coalition of races that centralizes itself at the city-planet of Courscant. Its main goal is to achieve cooperation and peace among all of its many members, and to encourage the trade of technology and resources to make the Galaxy a peaceful place where one need not fear traveling from one planet to the next.
The UGA meets the demands of the worlds within it through meetings in the Senate building on Courscant. Worlds send their leaders to meet and work out problems on their planet or within the Galaxy. The Senate hearings are largely majority-rule, making it difficult for some minorities to have any say. Still, it is argued that when you have a faction comprised of hundreds of members, it is difficult to make everyone happy.
The UGA is headed by a Galactic Prime Minister. Currently that office is held by a female Twi'lek by the name of Aai'Veda. A Galactic Prime Minister is elected/re-elected every 20 years.
With all the shared technology it possesses, the UGA has a tremendous armada of starships under its name (though worlds hold true control over the ships). Between the massive Death Stars and Executioner-class Star Destroyers, the UGA boasts the largest, most impressive ships in the galaxy, if not the Universe. Very little can stand up to the might of one of their large ships...and those that can are often brought down by the other, smaller ships that they can call to their aid. One of the largest strengths of the UGA is that a friend is never far away in times of need.