Forget about the National Party team, for a moment. New Zealand's politics have become leader oriented, even presidential in style. Parties rise and fall and rise on the character of the leader, presented not on a one-on-one basis with voters, but through the eyes of the media - a trend from which Mr Key and National have undoubtedly benefited.
Opinion polls have been the bane of the lives of politicians since the start of time. A general or local body election never passes without a political leader or mayoral candidate calling for opinion polls to be banned in the weeks before polling day. Such calls generally come from those near the bottom of the rankings.
There is a cliche in politics that the only poll that matters is on election day. But that is not true, a fact Mr Key will now be considering, because the latest opinion polls show Mr Key is slipping.
While he - and National - are not near the bottom of rankings, the Labour and Green parties will have received a boost from the weekend results. They showed that, if an election were to reflect the figures in the One News/Colmar Brunton poll, Labour and the Greens would be able to form a government.
Mr Key's rating as preferred prime minister dropped five points from February, to 39%, and National dropped six points to 43% - seven points ahead of Labour, which gained three points to 36%.
The drop in the 3 News/Reid Research poll was less dramatic, but nevertheless significant for Mr Key. They showed National slipped to 49% and would nearly be able to govern alone, but Mr Key's personal rating dropped to 38%.
Those who believe Mr Key is performing poorly went up by more than six points in the Reid Research poll - to 32%.
Although Labour also slipped in the Reid Research poll, and leader David Shearer had low support in both polls, Labour and the Greens would be able to govern based on the One News result.
This year, in particular, Mr Key has adopted a laissez-faire approach to the economy in general, focusing on overseas trips to South America and China as a way of increasing New Zealand's trading profile. One can never argue that New Zealand will survive without trade, but leaving Deputy Prime Minister Bill English to sell the Mighty River Power float and having a trip to China overshadowed by his role in the appointment of the head of the GCSB spying agency may have come back to haunt the Prime Minister.
Mr Key is the salesman of National's policies, and his absence during some turbulent times is starting to show.
Economically, New Zealand may be doing better than some Western counterparts, but many parts of the country are hurting. Glib responses, a threat to not answer questions from the media and a perceived lack of focus on domestic affairs have bruised Mr Key's numbers.
The latest polls were taken before Labour and the Greens released their plans to nationalise electricity, and it will be interesting to see if Mr Key will now try to sow doubts about the economic management of those parties.
After all, he knows the reason why opinion polls this far out from an election matter: another slip in his popularity as preferred prime minister - or in National as the party to lead a government - will see momentum rise for the Labour-Green pairing. And some voters like to vote for a winning party, no matter what their politics, feeling that to do otherwise is a wasted vote. Parties target those swinging voters when an election draws near. Momentum up or down in the polls undoubtedly benefits or hurts leaders - and their parties. Messrs Key and Shearer have it all in front of them.
