No; the number of bitcoins allowed to be mined is fixed per block. The NSA could womp up a bunch of ASICs and take the reward from almost every block, but that doesn't mean much; it would also take a long time to build up a big enough bitcoin hoard to really crash the market, and that would likely be a temporary setback inasmuch as miners are already selling a lot of mined coins and so a 'hoard' would have pushed up the price a lot in advance (supply & demand, right?) and everyone understands what has happened and takes advantage of the firesale. (If they had that much hashing power, they'd be much better off doing other attacks like double-spends and censoring other people's transactions.)