It was also archetypal Mr Key. Being a full about-turn, the reversal of National's stance on dealing with Mr Peters cements Mr Key's reputation as an arch pragmatist - a modus operandi which may end up defining his prime ministership.
Perhaps unfairly so. In terms of tenure in Premier House, Mr Key left Mike Moore, Sir Geoffrey Palmer and Jenny Shipley trailing in his wake long ago. He recently overtook David Lange and is closing in on Jim Bolger.
It all adds up to a heck of a lot of Cabinet papers and meetings. Mr Key, no doubt, will want to be remembered as a ''change agent'' - one who took the people with him. Witness this week's announcements on lifting school performance through salary hikes for the best teachers and principals.
It puts any reconciliation with Mr Peters into perspective. However, there will be many who will question the settings on Mr Key's moral compass instead. You cannot say you would rather lose power than work with someone and then turn around a couple of years later and offer not so much the olive branch as the welcome mat.
The change in attitude towards New Zealand First is further evidence Mr Key will do whatever has to be done to secure a third term for National on the Government benches in Parliament.
Even so, Tuesday's wiping clean of NZ First's slate was surprisingly deemed to be something of a surprise by some elements of the political milieu. The ''surprise'' may have simply reflected genuine amazement at the prime minister's gall in trying to execute a 180-degree shift in stance with as little drama as possible.
Or was the surprise a manufactured excuse seized upon by some as another opportunity to express indignation at what might seem to be more evidence of the prime minister's increasing willingness to flout principles he previously espoused?This case is very different, however, to the credibility-sapping episodes of last year surrounding Kim Dotcom and te GCSB.
There are mitigating factors in Mr Key's defence. The Labour Party may love Opposition - as an exercise in masochism at least. National in contrast has a bodice-ripping lust for power which is as core to why the party exists as its conservatism. Every National Party leader knows his or her survival is contingent on maintaining the uninterrupted delivery of power.
Mr Key is no different. Nobody should therefore have been surprised by the content of Tuesday's positioning statement declaring which political parties National can do business with after this year's election.
Surprise aplenty there would have been had Mr Key and his cabal of senior ministers who mulled over the carefully worded declaration reiterated the party leader's pre-election announcements in 2008 and 2011 that National would not be a part of any governing arrangement wIth New Zealand First which left National at Mr Peters' mercy and able to pull the plug on any such administration.
National's allies, however, do not look like returning to Parliament in sufficient numbers to enable National to continue to rule in the minority as it has done since 2008. Without Mr Peters agreeing to offer his party's backing on confidence motions - or giving a similarly binding commitment to abstain when such votes are held in Parliament - the whistle will be blown on National's six-year occupation of the Government benches.
It is unlikely Mr Key will incur much political cost from the U-turn, however. The public well understands MMP entails what David Cunliffe cleverly described as the ''dance of the desperate''.
Every time the Labour leader voices that refrain, it begs the question of what he would do if he was facing Mr Key's predicament. Saying he would not have got himself into such a pickle in the first place is not really an answer.
Mr Key's volte-face on Mr Peters was already under way long before this week's official declaration - another reason why the latter was hardly a surprise. Mr Key has conducted a softening-up exercise during the past year or so to get National voters attuned to the idea of life with Mr Peters again.
Whenever he was asked before this week about National not having the numbers on election night to govern, Mr Key consistently predicted Mr Peters was unlikely to opt for National because he had a strong dislike of the prime minister. Moreover, Mr Key kept saying he was convinced Mr Peters preferred to strike a deal with Labour.
What Mr Key was really saying was he was no longer ruling out negotiating with Mr Peters, but the latter would not play ball.
Then, as now, Mr Peters' response was to try to bury Mr Key with bucket-loads of invective, claiming Mr Key was trying to engineer the result of this year's election. Such diatribes only broaden Mr Key's smile - and for one reason.
Mr Peters has been consistent from election to election in stressing NZ First - should the party hold the balance of power - will talk first to the party with the most seats in Parliament. That party will almost certainly be National.
It is an advantage National will not squander. The big question is whether National will be willing to trade the one bauble of office which Mr Peters has never enjoyed (and which Labour cannot realistically offer) to secure his signature on a confidence and supply agreement.
Mr Peters has been a finance minister, a foreign minister and a deputy prime minister. That leaves one large and obvious gap in his CV.
Will National seek to find ways around the significant constitutional obstacles to enable the leader of a minor party to do a stint as prime minister obstacles such as could he realistically sack a Cabinet minister from the majority party?
It is assumed Mr Key will quit politics in National's third term assuming it gets one, Knowing he might get up to a year or so in the top job would be a massive incentive for Mr Peters to ensure, unlike its predecessor in the 1990s, a National-NZ First Administration actually goes the distance.
- John Armstrong is the political correspondent for The New Zealand Herald.