We need to chain up the government constitutionally for the same reasons we chain up our guard dog. If recent events don't persuade you how important those chains are, then nothing will. As Bernard Darnton summarises, recent efforts of the NZ Government to kill democracy are on a par with those of Pakistan's.
In 2005 they flouted election laws by stealing public money to buy propaganda. In 2006, they abandoned all constitutional norms and retrospectively changed the law so that they wouldn't be called into the High Court to answer for that action. This year the government has passed legislation allowing them to steal far more at the next election. Worst of all, the Clark regime is now trying to ram through legislation that would ban me from pointing out that they are behaving like tyrants and telling people not to vote for them.With Prime Minister Helen Clark currently in Uganda picking up tips from other leaders of third-word pseudo-democracies, constitutional chains including an entrenched Bill of Rights are becoming a matter of urgency.
UPDATE 1: Spelling mistake corrected. To say "Governments are like a guard god" is amusing, but incorrect.
UPDATE 2: In an irony of ironies, New Zealand has been appointed at the Uganda meeting to the Commonwealth's watchdog on democracy and governance. Rather like the UN's Security Council, the organ of the United Nations charged with the maintenance of international peace and security, on which over the last sixty years has sat some the world's greatest aggressors.