They can and they most probably have done that. Even Iran and China did it, stole root CA private keys, kind of sloppy because we know. Coercion by legal means

They can and they most probably have done that. Even Iran and China did it, stole root CA private keys, kind of sloppy because we know. Coercion by legal means, moles or good old hacking or planting bugged hardware in the targets system and extracting private keys. Its within the realms of NSA, remember, they have the capability to make their own processors.