The Alpha Centauri system is the nearest neighbour of Sol. It is home to Earth's first extrasolar base, the city of Port on Eden, set up by International Space Agency in the 2010s.
In the shadow of World War III, and sick of being used as a pawn in nationalistic warmongering, Eden declared indepedence. No-one was bothered to contest this, Alpha Centauri not being very strategically or economically useful.
It was in 2037, eleven years after the war, that some of the former ISA member nations attempted to reclaim Eden. They lost what later became known as the Battle of Alpha Centauri against a coalition of nations (Britain, Germany, Canada and Finland) that were minded to preserve Centauri independence.
Whilst still officially neutral in current international disputes, Alpha Centauri remains favourably inclined to its former saviours.
Alphacent survives mainly on tourism and education, the University of Eden being the major draw for both of these.