The United States took control of the island from Spain during the Spanish-American War of 1898, holding on to it apart from a short period of Japanese occupation through the formation of the UCAS up until the mid 2030s. When the UCAS decided to pull all of their forces out of the Pacific a local commander called Admiral Wallis and his supporters refused, joining up with local allies and staying to defend what they regarded as their home.
Admiral Wallis and allies go AWOL during the UCAS pullback to stay behind and defend the island.
Admiral Wallis was originally from Texas and is rumoured to co-operate with the CAS military, allowing them to use it as a friendly base from which to harass local Aztlan interests and monitor nearby shipping channels.
Whilst it is unknown what kind of government the country has, it is intimated that General Wallis and his military supporters maintain a large amount of either direct or indirect influence on the governance of the nation.
As the name suggest Guam Freeport makes a large part of its income operating as a free trade zone and from megacorporate shipping firms and scientific research vessels. It also serves as a refuelling and victualling port of call for ships as well as having a thriving grey and black markets.
Economy is based on megacorporate shipping firms, scientific research vessels, trade and as a port of call for smugglers, pirates and other shadowy types.