... because they'll fall into anarchy in short order. Then, America can invade them, conquer them, change their constitution, make them a Federal territory run directly by Congress, convert their people to Christianity, and basically rub their noses in it for a hundred years, just like the Roundhead Yankees did to the South.
You got in ahead of me.
Maybe there could be a Constitutional Amendment to the effect that Citizens have to be born in the United States, or resident for 70 years before they obtain voting rights.