With yesterday's confirmation of a tunnel as the second harbour crossing plus sundry motorway extensions and developments, Key has mapped out National's vision for Auckland transport and, perhaps more importantly, laid out the stages by which that vision will be achieved.
In one swoop, he has taken the steam out of what, after housing affordability, is the thorniest issue in the country's biggest city - traffic congestion - and one on which, according to opinion polls, National's management has less than impressed the public.
In particular, Key has now marginalised Labour and the Greens in the one aspect of public policy where those parties thought they safely had it all over National - public transport.
They have been left querying the 2020 start-date for the City Rail Link project, saying it should be much earlier.
Key, however, argues that the later date will see the work completed when patronage will be high enough to justify its construction. But he has left room to bring it forward if it becomes clear that Auckland's CBD employment and rail patronage growth hit thresholds faster than current rates suggest.
Apart from shoring up National's support in Auckland, the go-ahead is intended to remind the rest of New Zealand that National - unlike its opponents - looks at the big picture and gets things done whereas they are consumed by the relatively trivial, such as the fate of Peter Dunne and his parliamentary allowances.
For Labour - already wallowing in the Slough of Despond in the wake of its poor showing in the latest Herald-DigiPoll Survey - the tick for the City Rail Link was another reminder of how difficult it is to second-guess Key.
The irony is that Labour had a head start. The whole transport package was due to be released yesterday. However, Labour's Te Atatu MP, Phil Twyford, got wind of National's switch in thinking on the City Rail Link and tipped off some media organisations. In hindsight, he and David Shearer might have been better advised to have called a press conference and challenged Key to confirm National's sudden conversion to the wish-list of Auckland Mayor Len Brown.
Shearer would have looked proactive rather than reactive. He would have looked as if he had got one over Key.
But missed opportunities and tactical ineptitude are currently bedevilling Labour.
Labour "wallowing in the Slough of Despond"; it's the second time that Armstrong has pulled that line out, and it looks as though it might stick. And his comment about "tactical ineptitude" is right on the money.
Is Trevor Mallard still Labour's strategic genius?