Ultimately no matter how you judge the ethical performance of Brian Mulroney on his way out the door; knowing what we know now you cannot escape the conclusion that he displayed poor judgment and should not have been accepting envelopes full of cash from a shady arms dealer. Whether or not he deserves criminal prosecution is irrelevant because the evidence does not exist to prosecute the 71 year old former PM. We spent millions of dollars to confirm what was already suspected prior to the inquiry, that he should not have accepted the money and there is not enough evidence to prosecute wrong doing.
The man's legacy is tarnished and his credibility is in question. For more on the Oliphant ruling, I defer to John Ivison and Kelly McParland.