This is one of the most simple to argue & push for - making English the official language of the United States of America. Heck, the average American already thinks it is official. But it's sadly not. Of course most should think it is our language. It's been the spoken language since the British smacked out the pesky French and Spanish empires so long ago.
Then, when the colonials smacked out the British Empire, we retained English as the preferred language. That wasn't a mistake. After all, many of the immigrants to America came from non-English speaking countries. Be it France, Spain, Denmark or wherever, the rational man understood that language was either a wonderful unifier, or a sometimes insurmountable wedge between the unifying of peoples.