In that world, which is the proper written English: that of the Queen or that of her most loutish of offspring, America?
Is it absolutely necessary that the US exert its will in everything? When it comes to spelling, might the US simply acquiesce?
Americans need not adopt German, French or Cantonese, but rather alter the way a handful of words are spelled (or, perhaps, spelt). It is, after all, the English language, not the American one.