By programming the asset sales postal referendum for November 22 to December 13, the Prime Minister has now handed Mr Cunliffe a set-piece, government-funded opportunity to further bed himself in as the true Leader of the Opposition, and a future prime minister.
Among the opposition parties, this will be his chance to publicly reassert Labour's natural leadership role on the left, a position which under David Shearer's non-confrontational style had been steadily slipping, by default, into the hands of the Greens' Russel Norman.
Mr Key keeps repeating that the referendum is an "utter waste of money" because he's not bound by it, and that, yah sucks, even if he were, the latest asset sale, that of electricity giant Meridian, will be completed before the referendum is held anyway.
Of course, he's right in saying the referendum result won't stop the sale. But it's far from a waste of money as far as the political process is concerned, and he knows it. Otherwise, he wouldn't be trying to bury it at a time of the year when he's hoping most minds will be concentrating on pre-Christmas work parties, and sun-soaked beaches.
If he was truly worried about the $9 million cost of a stand-alone referendum, Mr Key could have waited a year and held it in conjunction with the general election. That would have exceeded the 12-month deadline set by law once the required number of signatories on a referendum petition have been verified, but Labour has already said it would back a parliamentary vote for an extension of time.
Obviously that wasn't a palatable choice for the National Party campaign organisers, who saw the pitfalls of fighting an election alongside a referendum about which the majority of New Zealanders will side with the opposition parties.
Instead, they've chosen the potentially messy tactic of having a referendum campaign that coincides with the Government-backed publicity drive to persuade Mum and Dad investors to sink their savings into Meridian shares.
With the sharemarket listing timetabled for October 29, the Government will be hoping the share price doesn't sink drastically in the following month leading up to the asset sales ballot, as happened after the first power-company part-privatisation, when Mighty River shares dropped from $2.50 to as low as $2.17. Such a setback would just add to public negativity.
For Mr Cunliffe, the big challenge will be in cranking up the creaky and poverty-stricken party machine he has inherited, to get out the vote. History is not on his side. On December 2, 1995, in the first citizens-initiated referendum, a miserable 27 per cent of those eligible bothered to vote on the admittedly less than riveting issue of whether the number of fulltime professional firefighters should be maintained at existing levels. For the record, almost 88 per cent of those who dragged themselves to the polling stations voted against any cuts.
The subsequent three citizens-initiated referendums were conducted either in conjunction with a general election or, in the case of the anti-smacking referendum of August 2009, by postal ballot.
That emotive issue attracted a respectable 56 per cent return, of which 87 per cent said smacking a child should not be a criminal offence.
The challenge for Mr Cunliffe is twofold. First, he has to assemble a fighting fund and team in just a few weeks to ensure a turnout at least as large as that for the anti-smacking poll.
The incentive for him is that Mr Key has handed him the perfect opportunity to anchor himself, both to the media and the voting public, as the true Leader of the Opposition.
For National, the timing was all about trying to bury an embarrassing topic. But in doing so, it has given Labour's new leader another month on the public stage to take potshots at a government policy that most New Zealanders dislike.
For Mr Cunliffe, it must be like a Christmas come early.
