Government isnt a threat to bitcoin - bitcoin is a threat to government.
Government will be a threat to Bitcoin - depending on Bitcoin's success rate. The financial elite who control governments will not sit idle and watch Bitcoin take over a large share of trade/"money" transfers.
I would mention that "attack" does not equal "be a threat". A quadroplegic in an old-fashioned wheelchair can "attacke" me all he wants, but I being a paraplegic in a more advanced wheelchair will not be threatened.
I am curious as to what the financial elite/government/illuminati/reptilians could do besides sit idle and watch bitcoin take over. And please something more than "they could declare it illegal/shut down the exchanges"