Also it's pretty much impossible to patch and protect against, even if you know the exploit exists.
But let's think in a wider scope (disclaimer: this is not my idea, I remember reading about it a long time ago): what if a certain cryptographic "magic code" at the beginning of a memory page would trigger the execution of arbitrary code embedded in that page?
Such a thing could be triggered over the network, wireless through bluetooth/wifi, or by specially crafted images on a webpage, or whatever creative technique you can think of. It'd effectively give the govt instant root access to any device with the affected CPUs.
It'd be mighty interesting to tear apart / scan / reverse engineer some modern CPUs like they did with the 6502. Then again, these beasts are so complex that's similar to looking for a needle in a galaxy-sized haystack.
Even more scary is the thought experiment that Microsoft might cooperate with the Tunisian government and allow installing trust for such a root certificate via the windows update mechanism. (I have no evidence that this actually happens, it just seems a convenient vector)
[1] They're under no time pressure and can transparently proxy every single TCP connection and IP packet if they so desire. They control DNS.