#12 a national language

Moscow to press Latvia to give Russian language official status
http://en.rian.ru/russia/20071106/86889684.html

A little background
Russia has been recently pressurng Latvia to declare Russian as its official national language. As of today, Latvia is the only ex-Soviet country where Russian is still treated as a foreign langauge, even with 30% of its population identify themselves as native Russian speakers.

After reading this article, I found myself asking what the use of an "official" national language is. Even with 96% of the US population speak English (82% are native English speakers), the United States still hasn't announced English as the official national language. After a little research, I've found that the giving a language an official status can also be done not only to declare its dominance, but also to protect less ubiquitous, indigenous languages. Interestingly enough, this seems to be the strategy Russia is taking. Russia argued that Latvia must declare Russiian as the official national language because many "large ethnic Russian population in Latvia and Estonia have been assigned "non-citizen" status, which denies them a national passport and other rights, and prevents them from voting." There seems to be the logical connection between declaring an official language and the subsequent enfranchisement of basic human rights.

However, if we were to follow this train of thought, how would the US fit into the picture? Even though an overwhelmingly large percentage of the population speak English, there hasn't been deemed a need to proclaim English as the national language. In fact, though most legislative and official documents and proceedings are conducted in English, many states have provided for foreign language translations of these official documents.
What explains the rationale for the United States not to make English the official language? I think Congressman Mike Honda puts it best in his article

Immigrants' language skills crucial in era of global economy
http://www.mercurynews.com/opinion/ci_7374151?nclick_check=1

when he says that "multilingualism not only culturally enriches our country, but it makes long-term strategic sense if we want to remain the leader of the free world in a global era." By not enforcing a national language, foreigners are then, at no official pressure (social pressure is a different story) to discard their ancestral tongue and force themselves to speak English. However, I still wonder: what are the advantages of giving the predominant language "official" status, and what are the social implications of that? In short, does Russia have ulterior aims in forcing Latvia to give Russian official status? What do you guys think?

Source
http://en.wikipedia.org/wiki/Languages_in_the_United_States