The american intelligence agencies have no incentive to bring down bitcoin. Unless the NSA receives an executive order to kill bitcoin, they simply won't do it.
& the CIA's jurisdiction is outside the USA. If anything, they would benefit from BTC because they can do all manner of covert payola ops to foreign bad guys and the like. If Ollie North had btc he would have never got caught. my guess is they already have btc and are looking to move it on to all the shifty terror groups they do business with on a daily basis. crime pays, especially if you the gubmint!