It may be tempting to argue that serious criminals should not escape charges of which there is good evidence, even if it is improperly obtained. And the law agrees: the Evidence Act provides that illegally obtained evidence may be ruled admissible if the offence alleged is of a sufficiently serious nature.
The Supreme Court exercised judicial discretion under that very provision in allowing charges against four of the remaining Urewera accused to proceed.
But retrospective legislation validating illegal police conduct is a serious violation of our freedoms as citizens. The idea that police are not above Parliament is deeply rooted in our constitutional framework and our justice system.
The law prescribes procedures that police must follow, not to make life difficult for police but to protect citizens from arbitrary exercise of police power. The word for a country where such protections do not exist is not a democracy: it is a police state.
Experienced defence lawyers quite reasonably demand that Key name an active case relying on the evidence under discussion. Police need not prejudice ongoing investigations, but in some of those 40 cases, they will have already disclosed what evidence they have.
The Supreme Court ruling, remember, applies only to filming on private land and the Government needs to demonstrate the urgency it claims.
The fact is that the High Court ruled two years ago that what the police had done in Te Urewera was illegal. That decision was overturned in the Court of Appeal, and in turn reversed in the Supreme Court this month.
The idea that this bombshell decision has just been dropped in their lap and that Parliament must suspend its normal procedures to take drastic and objectionable legislative action is unsustainable.
In handing down the Supreme Court decision, the Chief Justice said that the police actions were "destructive of an effective and credible system of justice ". A hasty law change that hands a blank cheque to the police is not the way to repair the damage done.