The South American Union picked the San Andres colony with care. It was in a largely unexplored sector of space, but there was a star in its neighborhood that might be able to connect directly back to Alpha Centauri. Even the Big Three hadn’t managed to find the hyperspace run connecting the two systems from the Alpha Centauri end and abandoned thoughts of the system. South America sent their best scientists out to San Andres, and then to the world that would become San Santiago. It took them years to lock down the hyperspace run back to Alpha Centauri, but once they did, it opened the entire sector up to a new wave of human expansion. The Union Council finally had the big discovery that could bring them riches unimaginable to Earthborn minds.
The South American Union first ventured to unwanted stars. San Pedro, San Mateo, and San Marcus orbited dim or distant stars that took years for their hyperdrives to reach. The Big Three targeted stars they could reach and exploit far quicker and left those systems alone. And Union colony ships moving to San Lucas and San Juan required long transits through systems owned by other nations. The Union spent the better part of a century colonizing and investing in those five colony worlds, efforts that mostly resulted in backwater vanity projects that would never affect interstellar politics. Most of the colonists were rugged types that enjoyed backwaters, but they were far from returning the investments poured into them. The Union Council was not amused.
The South American Union is well-named. It is a union of independent Nation States. They have a Union Council, and each State in South America and each off world colony has a single seat on it. They elect a President from their number who is authorized to perform foreign relations and run a military much like many nations. But a simple majority vote of the council can abrogate any decision made by the President. Or remove the President altogether. Of course each Councilor only serves a single four-year term, with a quarter of them replaced each year to make certain there is a constant influx of new blood and the old blood are soon retired. This keeps the central government from growing too big for the States to keep in check.
The South American Union and all its colonies are rather more rough and tumble than most other nations. For one thing, it should be no surprise that they are rabidly anti-Communist given their history. The Communists killed far too many South Americans for them to forget. They don’t even trust the milder Socialists that have taken over some parts of North America, and South America will join no alliance that accepts them. Wherever they go, every colony maintains honor guard helicopters maintained specifically to deal with Communists, and those helicopters fly in every national independence celebration. They even shoot showers of confetti, to the cheering amusement of children everywhere. Converting bad Communists into good Communists is fun for the whole family.
The South American Union arose out of the fires of the violence accompanying the Second Great Depression to become a major world power. They may not have been one of the Big Three, but they had no wish to survive under the benign, at best, neglect of anyone else. They move into space on their own, built their own orbital elevator, and planted their own colonies on the Moon, Mars, and beyond. They even went to the stars on their own terms and colonized worlds and systems as they could. Though they did cooperate with the Western Alliance when it came to colonizing some of the open worlds like Pacifica, Paradisia, and Serenity. They had no reason to antagonize the Alliance after all. Playing nice rarely hurt anyone.