I am in favor of the US naming English as its official language. It would be silly for this country to name any other language as it official language. English is what we are taught in all the public school systems around the US so this should be common knowledge.
Every country has an official language, so it seems fine that we have an official one. That doesn't mean translators should not be available or that we should not value the cultures of those who are immigrants, just that we should assume everyone will be trying to learn English to do well here.
Without a doubt, the official language in the United States should be English. The overwhelming majority of people speak English in the country, and there's no reason to make any other language the dominant one. The country needs to recognize American English as its actual language rather than keeping it an open topic of debate.
The US does not have an official language mostly because Congress does not, and has not, had the authority to declare it as such. Each state should be allowed to set its own language, and the states should definitely declare English their official languages, but the federal government should not be part of the process.
The United States was formed on the basis it would become the great melting pot of freedom for several cultures. As such, English should not become an official language simply because a majority of Americans speak another language. In 20 years, whites will become a minority. Hispanics are quickly growing as a formidable voting bloc. As such, English should not be the official language of the United States.