Such is the schizoid nature of MMP politics that one moment you can be slagging off rival parties, only to find yourself needing their help the next.
National's message to voters in the final days of the campaign is simple. It is the only party that can guarantee a strong, stable and low-debt Government in difficult times. Any arrangement Labour might cobble together will be inherently unstable.
That theme was underlined yesterday by Steven Joyce, the minister in charge of National's campaign, who said the Greens' policies were so "eye-wateringly expensive" that a Labour-Greens government would borrow an extra $25 billion over four years.
But come Saturday night, it is a pretty safe bet that regardless of how the chips fall, sooner or later John Key will be on the phone to those very same Greens, assuming National is the party that has won the most seats.
Such a call will not be an immediate priority if National is either in a position to govern alone or with Act and United Future.
Key is intent, however, on building a long-term relationship with the Greens. He will want a fresh and extended memorandum of understanding with them in policy areas where the two parties can co-operate.
The question of something stronger - such as a deal on confidence and supply - may be academic. The Greens would require big policy concessions. Being in a position of strength, Key would be silly to oblige.
The phone call will be made a lot sooner, however, if Key needs help to secure a parliamentary majority, especially if National's nightmare scenario eventuates in the form of Winston Peters influencing the balance of power.
All eyes would turn to the Greens. The possibility of them backing National by either supporting Key on confidence and supply votes or, more likely, through abstention on such motions would be the obvious solution.
So obvious that it is possible to envisage the Greens coming under huge pressure to reach some kind of accommodation with National which shut out Peters.
That the Greens could find themselves in a very tricky position post-election loomed large in the circumspect replies from their co-leader Russel Norman on Radio New Zealand's Nine to Noon show yesterday. Norman conceded if National offered sufficient policy concessions, "we would consider it".
Given the antipathy towards National within his party, Norman went about as far as he could. The lasting impression was that one way or another, National and the Greens will talk turkey after the election.
Key may not even need them on board. But if he does, it will be rich irony if the stability Key and Joyce are promising is contingent on the Greens.