Your long winded analogy is flawed on so many levels. Let me correct it for you. We will stick with the Americans vs Aliens scenario:
The Aliens and Americans were part of the same country for quite some time. The aliens had originally conquered America, and America became intertwined socially, economically, culturally and even genetically. One day, the aliens government fails, they spin America off into its own country, and left some of its people behind, as they have been there many generations. The Americans then treat the aliens as second class citizens, Balkanized into a section of the eastern seaboard, near the aliens mothership. They will not acknowledge the alien culture or language, even though it's quite similar to standard Murrican. To the uneducated outsider there is barely a difference racially, culturally, linguistically, but nonetheless they see a difference.
The American government proceeds to supply its militias and tacitly supports them as they shell, machine gun and harass the aliens. Aliens are killed by the thousands over many years, all the while the world turns a blind eye. The new alien government in the mothership scolds America and warns they will use their death ray to attack America if they don't stop.
America does not stop, and the violence escalates. In response, the aliens hover their drone ship over Boston harbor and use their ion canon to capture the area. The americans are completely unprepared and are easily overwhelmed.
Some peace accords are made, but they are soon forgotten, and America resumes punishing the aliens but now they're armed with more advanced weapons supplied by the rest of the worlds militaries.
The aliens continue to warn America, and posture their clone army, and the attacks continue. This time, the aliens deploy their mothership and launch a ground invasion.
That was at least 500% more apt than your analogy.