The Republic of Cortina is an American ally on the fictional island of Aragon. As many of our allies are in these training environments, Cortina is rich in natural resources. It is also rich in political corruption and ethnic violence. This makes them an easy target for the Cortina Liberation Front that wants to topple the government and bring in a new era with them or their masters in charge. This would obviously not be good for our Cortinan allies, so American troops are often sent in to protect our fictional allies from their dastardly foes. Those foes are funded by the Peoples Democratic Republic of Acadia, which absolutely wants to take over the entire island of Aragon. If my information is accurate, the 509th Infantry Regiment often plays these guys against visiting Army regiments, making them a valuable training aid for the US Army.