The reason a national language is a sticky issue is the minute Congress tries to enact one, the Spanish-speaking lobby rolls out the big guns and argues for Spanish to be the national language. And, with a much greater percentage of Spanish-speakers willing to go to the mat (or the voting polls) for their languange that there are English speakerrs willing to do the same, the outcome quickly becomes a bit scary
no matter how far-fetched the likelihood that Spanish would actually get chosen above English.