Caucus must seek the consent of the party to alter the election policy platform.
If these changes were in place in the mid-1980s, Roger Douglas and his right-wing cronies could never have succeeded in carrying out their coup d'etat.
The enthusiasm and attendance at the conference was well up on recent years. It was good-natured and energised. The mood reflected a party that knew it could win the next election. Ironically, David Cunliffe's not-so-subtle ambitions turned into a benefit.
The question in the party all year has been, did we pick the right guy as leader and is he up to it? Cunliffe's supporters have kept a constant underground campaign stoking doubts about Shearer. Anyone who denies that is being disingenuous.
Cunliffe's media interviews, including on TV3's The Nation last Saturday morning - the middle day of conference - was calculated to reinforce his media skills to the party faithful, in contrast to Shearer's.
Although the 40 per cent voting threshold would possibly have won over the 50 per cent option anyway, it was evident many of the main supporters of the lower threshold were Cunliffe backers.
The rumour was Cunliffe and his supporters planned to build his profile extensively over the summer, arguing Shearer was incapable of winning.
Deals would be made and by February he would garner the requisite 12 MPs to vote to force a new leadership election. From there they hoped to use a majority of unions and party blocs to install Cunliffe as the "left wing" choice.
Cunliffe's newly established left credentials are just that - new. Cunliffe's confidence and arrogance led him to overplay his hand at the conference, and effectively ended his political career.
Instead of Shearer making a pedestrian speech, as Cunliffe's supporters expected, he knocked it out of the park. His headline announcement to build 100,000 homes was breathtaking in its audacity. It wowed the party base and reassured doubters in one swoop that, in contrast to John Key, he actually has an economic plan.
Even the most economically illiterate could see it would create thousands of skilled jobs, as well as solve our housing crisis and give the working poor a stake in the game.
Shearer then delivered the coup de grace. Instead of waiting for February, he called an urgent caucus and put up his job for a vote. In a more gutsy move, he announced beforehand that he no longer trusted Cunliffe and would dump him.
Cunliffe and his dwindling supporters dutifully raised their hands for Shearer.
What's that line about turkeys and Christmas?
The claim that Cunliffe has done nothing wrong doesn't wash. When Shearer won the leadership, he put Cunliffe and his running-mate on to the front bench. For much of that time, Shearer's supporters say Cunliffe has been missing in action and running a covert campaign against the leader.
Doubt about Shearer being able to motivate his party, or being tough enough, is over.
In February there will be no challenge. Instead, Shearer has cleared the field and can lead his party to victory.