Goldsmith's conclusion is worth noting for the lesson it provides in minimizing leaks:
How can we maintain the virtues of a vigorous press, but minimize the disclosure of secrets that should remain secret?(emphasis added)
The answer to this large question lies with the executive branch of government. Many people think that the executive branch should crack down more on leakers, because the regularity of leaks without sanction legitimizes leaking and leads to more. The Bush administration has tried to punish those who leak details of its surveillance and interrogation programs... And even when leakers are discovered, it is hard to prosecute them, for many of the same reasons that it is hard to prosecute members of the press--poorly drafted laws and fear of disclosing leaks.
Yet the absence of sanctions is not the real problem. The real problem, and the source of many of the most harmful leaks in the past few years, is the perception within the government of illegitimate activity. Secret surveillance activities that began in 2001 did not leak until after a legitimacy crisis had already developed, beginning in June 2004, around the Abu Ghraib scandal and the leaked interrogation memos. Lichtblau explains that it was the Terrorist Surveillance Program's circumvention of checks and balances, and the attendant anxiety about the program's legality, that led people inside the government to tell him about it...
A root cause of the perception of illegitimacy inside the government that led to leaking (and then to occasional irresponsible reporting) is, ironically, excessive government secrecy. "When everything is classified, then nothing is classified," Justice Stewart famously said in his Pentagon Papers opinion, "and the system becomes one to be disregarded by the cynical or the careless, and to be manipulated by those intent on selfprotection or self-promotion." And he added that "the hallmark of a truly effective internal security system would be the maximum possible disclosure," noting that "secrecy can best be preserved only when credibility is truly maintained."
In short, the leakers aren't just those not "on board" with the policies, but those who doubt their legality and have no alternative but to leak. Being more transparent, listening to internal criticisms and engaging in a real dialog with those who are enforcing such programs addresses the root of leaks more effectively than threats of retaliation.