It's never been clear to me why NSA's "blue team" directorates haven't been spun off into a separate agency. Sure, NSA strengthened the S-boxes in DES and SHA-1 but from the outside there's no way to know whether they're making DES stronger against differential cryptanalysis or whether they're introducing a DUAL_EC-style vulnerability.

I'm sure there's a game-theoretic optimum choice when it comes to accepting proposals from the NSA vs rejecting them out of hand, but I'm not sure what that optimal choice is.