How much should we trust Prime Ministers?

Two of the biggest recent controversies concerning intercepted communications – the Key–Banks 'cuppa tea' conversation, and the release of phone and email records to the Henry inquiry – arose from incidents that had little potential to cause any really serious harm.
If you had a chance to read the tea-pot conversation transcript, you'd know there was little of great interest in it, other than a couple of off-colour remarks that could well have been covered with an apology. That recorded conversation would not have passed the legal test of a 'private communication' as it was held in a very public situation, and there was no evidence found of intent to intercept it, so there was probably no crime done. (The matter was never tested in court, so I guess we'll never know for sure.)
Similarly, despite all the fuss, Peter Dunne's alleged release of the Kitteridge report to a journalist was not really a big deal. It was not classified, and was due for public release anyway. What may have really upset the PM was that the matter then dominated headlines while he was away in China and wanting media attention to focus on what he was doing there.
So, even though both events could easily have been put to rest quite quickly, the government of the day decided instead to turn them into witch-hunts. In the tea-pot tape incident, we saw police exercising search warrants on media organisations in the days leading up to an election. We have read also that the search into the accused cameraman's text messages could also have breached the confidentiality between lawyer and client. Not a good look for a country that prides itself on respect for civil and political rights.
In the case of the Henry inquiry into the release of the Kitteridge report, we have witnessed the PM's staff reaching into parliamentary services' records, apparently without the Speaker's knowledge. In investigating who released a document that was going to be released anyway, even greater damage has been done to the principles of confidentiality of journalists' sources and of separation of powers between the executive and the legislature.
Both incidents produced significant political and media-coverage impacts – but unnecessarily so, I argue. The PM, and people close to the PM, could have reacted less aggressively than they chose to.
Let's add to this the facts that (1) we must now assume that international spy agencies are hoovering up every bit of electronic communication that gets emitted from anywhere on earth, and (2) the present government would like to pass a law permitting the usage of such communications intelligence for domestic policing. They have made it clear that they might wish in future to allow other governmental agencies (beyond the police, SIS and defense force) to utilise this data. And the control of the intelligence agency concerned is largely in the hands of the PM. It does not have the statutory independence enjoyed by the police, for instance.
Keep in mind that your smart phone records your location, and the metadata that it produces will reveal what you are reading and whom you chat with. We, the people, have to ask whether we wish to live in a society where, for instance, anyone even vaguely suspected of some form of tax-evasion or 'under the table' cash jobs or working without a work-permit can be detected by such means. Even though we may disapprove of such actions, knowing them to be illegal, and even if we are personally not guilty of such things, we have to ask just how much policing and surveillance we are prepared to accept in return for security and the rule of law.
Yes, we do expect that people who may be preparing to launch bomb-attacks are monitored and apprehended before they can carry out their plans. But the present criminal law and powers of search and surveillance should be sufficient for the time being. And if the police and others need more powers, then those powers must be justified openly in public forums if they are to be legitimate. Just as we have had vigorous public debates about police officers wearing side-arms, so we need an equally vigorous debate about communications intelligence techniques (that were originally meant for monitoring foreigners) being applied domestically. And that debate needs to be an informed one. We need to know exactly what are the technologies in use and how intrusive they can be. The public are being duped by the GCSB Bill's application to New Zealanders, as no-one is telling us what the GCSB is actually able to do. Secret policing is not acceptable in a democratic society.
An irascible Prime Minister who throws more weight than he needs to at those who merely embarrass him is not a person whom I'd trust with even wider powers than he presently exercises, let alone secret powers. And, of course, we don't know what future leaders might be like...
It's obvious that many opposition MPs are concerned about the extensions of policing powers presently before the House, but too many gutless others are staying quiet and refusing to pay heed to widespread concern.