A - Making learning a 2nd language mandatory
and
B - Making English the national language
I don't see why the two are mutually exclusive goals. Americans could profoundly benefit from being bilingual, both in the simple utility of knowing multiple languages, and in having their horizons broadened by doing so. I also think that anyone that comes to this country should adopt English as their primary language, and expect to use it for all official or business related affairs.
Hey, I met my wife in a Spanish class at the YMCA 45 years ago! I wanted to go back for more fun in Mexico, and she was a just-licensed RN who, even then, was having to deal with non-English speaking patients. (We went to Mexico on our honeymoon).