When the government’s espionage case against former National Security Agency official Thomas A. Drake collapsed last year, it meant that a key defense witness didn’t get to take the stand.

The witness, J. William Leonard, the government’s former classification czar, planned to testify about the harm to democracy represented by the case — not from Drake leaking information about a troubled counterterrorism technology program at the NSA, but from what Leonard viewed as the government’s needless classification of information.