Why not leave it to the private sector?
Edit: Then there's TrustedBSD (as opposed to SELinux)
I had found a backdoor in their platform, so I asked if they had such basic holes, how they managed to write a large C-based app securely. Like, buffer overflows, for example.
CTO/head of development replied: "Buffer overflows? Probably not an issue, unless the network is really fast." Cringe.