What mattered in the Ardern announcement was that Labour dressed up this promise as its own - not the Greens. But she also neatly wedged National into a corner by saying Labour would adopt Auckland Mayor Phil Goff's proposal for a regional fuel tax to part fund a stepped-up programme for Auckland's public transport infrastructure.
The policy in effect adopted a number of measures put forward by Greater Auckland - formerly known as the Transport Blog - particularly from its Congestion Free Network 2 proposal.
Among the policies:
• Build light rail from the CBD to Auckland Airport as part of a new light rail network that will be built over the next decade with routes to the central suburbs, the airport, and West Auckland, and will later be extended to the North Shore.
• Build a new bus rapid transit line from Howick to the airport, starting with a bus service which will connect Puhinui train station to the airport in one year.
• Invest in more electric trains and build a third main trunk line urgently between Wiri and Papakura.
Labour will also look into more funding options for Auckland including bonds as previously floated by MP Phil Twyford.
While there is inevitably some cross over with National's own suite of transport policy options, Labour has played to the progressive element of the Auckland infrastructure debate. The upshot was an immediate validation of Ardern's stance by Greater Auckland and Generation Zero.
Although Greater Auckland did take issue with the "bogus" congestion cost figure of $2 billion that Labour used in its pronouncements.
Much of National's policies are derived from the Auckland Transport Alignment Project. This project was formed by central Government, Auckland Council, The Ministry of Transport, Auckland Transport and the NZ Transport Agency to get common agreement on priorities for developing Auckland's transport infrastructure. The ATAP Foundation Report highlighted the opportunities and challenges arising from Auckland's growth. It said, while growth provides opportunities to capitalise on the benefits of a larger and more diverse labour force, driving productivity and prosperity gains, it also places pressure on transport networks leading to congestion, overcrowding and delays. Funding constraints are - and will remain - an issue.
And while the Greens self-destruct - helped along by Ardern's bottom-line that she would not have their co-leader Metiria Turei in her Cabinet, Ardern is lining up for another territory encroachment. This time it's on water levies. Exporting bottled pure artesian water from NZ's ancient aquifers is a polarising issue. Ardern says there needs to be remuneration for water used for profit - in the same way the state extracts a levy or royalty for mineral exports.
The Greens, who got there first, have been so hell-bent on self-destruction that they have taken little notice of the latest policy grab which will provide yet another reason for Labour to pull back some of their supporters who have been appalled by Turei's stance on benefit fraud.
Not so NZ First leader Winston Peters who said he was "bemused" by Labour plans to copy the party's policy on bottled water.
"We've had our royalties on bottled water export policy for well over a year ... but now, as the election nears, Labour is trying to get in on the act and is talking about a 'levy' - just a new word for 'royalty'."
The upshot of Ardern's second tactical play is that National - which has shied away from the pricing water debate - will be once again on the back foot.
Sure the last week has seen NZ politics at its rawest.
But this election will be a complex game with several potential winning alliances.
Ardern has shown she is good at the tactical play but we have yet to see what her long-term strategy is.
