"Military action" and "prosecution" isn't needed to ruin the project folks. Bitcoin is as strong as its users' collective computer power. In other words: NSA > Bitcoiners
Of course, this (unlikely) scenario is part of the motivation for regular blockchain benchmarks being encoded into the source code of new releases. So your attacker would still have to come up with a fake blockchain that not only matched those benchmarks precisely without violating any of the other valid block rules on any of his fake blocks and have such a blockchain ready that was at least as long as the benchmark shipped in the latest version before the standing network would receive it.
I think we can all agree that the NSA
already has its fake chain ready to launch at any moment if they deemed Bitcoin a serious danger to the US economy. They probably started working on it from day one, even. It would be identical to the real one except that it's a couple of blocks longer. Those couple of blocks rip everyone from their coins. End of story.
And if any copy of the real blockchain were to be reintroduced to the network before the fake one could develop a greater total proof-of-work, the real blockchain would force a network split that would eventually destroy the fake one.
Only if the real one posses more total computer power than the fake one, which is not the case with the NSA.