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.
During the campaign, Mr Key can expect a far more searching examination of whether his administration is doing enough in response to the ravages of the global recession.
There are other possible potholes for National. Two of its allies in government, the Maori Party and Act, appear vulnerable. Act, especially, is highly unlikely to replicate success in having five MPs, and may well survive only if Mr Key instructs Epsom's National supporters to vote for the Act candidate - and they obey. National may yet have to seek out new partners. On the other side of the coin, the Greens are poised to poll well, partly because of disaffection with Labour. Should National trip up, it is not beyond the realms of possibility that the Greens could hold the balance of power.
If that were to happen, they would face a quandary. The party has left the door to an accommodation with National slightly ajar, much to the annoyance of some of its members who want nothing to do with a centre-right party. But the Greens' pragmatic leaders also know that a legacy of the first-past-the-post system is that the party which wins the most votes is generally considered to have won the right to form a government.
The expectation is that National will govern for a second term. But there are enough ifs and maybes to render the four weeks of campaigning far from irrelevant and the result far from a foregone conclusion.
National no longer has the convenient distraction of a big sporting event. Much more attention will be paid to the actions and utterances of Mr Key and his party's candidates. They will be assailed by events, perhaps a new tremor in the world economy, perhaps something engendered locally. Much still depends on how they respond.