But the main reason Prime Ministers pull stumps after losing office is that they can't abide the dismal prospect of Opposition after experiencing the joys of high office.
John Key has been open about resigning when his time comes. What puzzles me is why after defeat, ambitious Opposition politicians clamour for the leader's role despite knowing history is against them. For example, Phil Goff had excellent credentials to eventually become a successful Prime Minister but blew it by pursuing the leadership too early.
In the postwar years National boasted they were the natural party of government, a claim borne out by them being in office for 38 of the century's last 50 years. Of the three Labour Governments over that time only David Lange managed a second term. On the other hand, the four National Governments since 1949 won three, four, three and three successive elections.
All of that augurs poorly for David Shearer. But that's on face value. Closer analysis shows this pattern changed in the 1990s.
Jim Bolger just scraped home in 1993 (remember his election night "bugger the polls") and had Winston Peters honoured his pre-election pledge not to get into bed with National, Labour would have won in 1996. In short MMP has changed everything and it may well prove that it's now Labour, not National, which is the natural party of government in the foreseeable future. History shows support for governments erodes sharply in their fifth and sixth years, this being the political pendulum in action.
Currently the polls are throwing up erratic results but the standard seeds of disenchantment are certainly there. The Education Minister, Hekia Parata, somewhat unfairly, I suspect, is under ferocious attack from all quarters. The Justice Minister, Judith Collins, is disliked for her appalling arrogance, the Prime Minister's unseemly dealings with a casino are upsetting many and you may be assured there will be further disasters.
It probably sounds silly but the polls no longer matter as they did under first past the post. Holyoake was fond of pointing out that polling 18 months out from an election accurately foretold the result, and so it did. But MMP, with its multitude of parties, has changed all that. For example, had Winston not reneged on his pre-election promise in 1996, Labour would have been in office despite their lowest percentage vote since 1932.
John Key's common sense and easy-going charm are the Nats' biggest asset but time and familiarity invariably diminish that. David Shearer's affability and evident decency could prove the perfect antidote. But Shearer must be careful about silly promises which could prove an albatross in an election campaign. The ill-considered 10,000 cheap new houses annually is typical. For several reasons it can't be done. The Government is quiet about this, I suspect hoping to lambast Shearer for it in next year's election campaign. So too with the vague undertakings to bring down the exchange rate. Safe stuff like raising the minimum wage and shifting the school holidays to February is the way to win.
The great advantage of Opposition in an election campaign is the ability to attack a Government's errors and it is foolish in the extreme to hand that same opportunity to a defending Government.
Walter Nash won in 1957 with a preposterous bribe but the next three Labour Governments, led by Norman Kirk, Lange and Helen Clark, made no silly undertakings but sailed in simply because voters had wearied of the Government. "Time for a change" remains the most effective Opposition slogan.
Legendary boxing trainer Angelo Dundee once said to me, "all adversarial activities are won by those setting the agenda". Labour should remember that and ensure the agenda is the Government's performance and not their own wild commitments.
