If many voters feel a sense of inevitability about the November 26 general election, it is surely not shared by the two main parties. Even with odd decisions, such as Labour eschewing automatic publicity by not joining National in an official campaign launch this weekend, nothing can be taken for granted.
If some polls suggest National may win enough votes to govern alone, history confirms the gap between the two parties usually tightens considerably as election-day approaches. In part, this may reflect the normal nature of things, but it is also a consequence of the issues that, out of the blue, always crop up during campaigns.
Those in the National camp guilty of over-confidence need look only at a similar scenario before the 2002 election. Helen Clark's quest for a second term looked a formality until she was ambushed by claims her Government had covered up possible GM contamination of imported sweetcorn.
The grounding of the Rena could have caused similar damage to John Key. The Prime Minister has been lucky, however, in that the episode occurred during the World Cup and good weather has enabled oil to be pumped from the stricken ship.
National starts its campaign with the advantage of a tailwind thanks to the All Blacks' success in the World Cup. A sense of satisfaction pervades the country. The event has also been a distraction, not least from the downgrade of New Zealand's sovereign credit rating by Standard & Poor's and Fitch.