There is no direct link between leaking and credibility. In fact, the opposite is often the case. What Comey released to his friend in order that it become public was neither classified nor secret, and it was essentially the same information that was in Comey's opening statement released yesterday by the Senate committee. As he stated several times in today's hearing, there exists information that could not be revealed in a public setting, and that information was not a part of what he "leaked" either.