north Americas navy fends off invasion from Europe and Asia while they quickly deal with south america (is that even really a contest). Europe defends against African invasion from Gibraltar while their navy is defending the Mediterranean and the arctic sea; European forces mostly massed Asian borders. Asia, Europe, and Africa all fighting over middle-east (Asia likely victor considering numbers and technology). american (america will refer to both north and south american forces from here on) troops begin invading Africa, leaving Europe and Asia in bloody stalemate weakening both sides. america pushes into mid-east (easy conquest considering the weakened Asian forces). america proceeds to push into Europe through Gibraltar and Istanbul. after securing the Mediterranean, america begins invading southern Italy. after taking europe america invades Australia (who hasn't done much) while simultaneously invading asia. after much bloodshed and loss of life, north america and its 'liberated' allies emerge victorious. [spoiler]i've actually thought about this scenario quite a bit[/spoiler]