If the Budget seemed like smart politics at 2 pm when it was clear National had made yet another raid into Labour territory, by 7.30 pm it had turned into a work of sheer genius when it was clear the Greens were going to support National's tax reduction law.
Labour alone opposed the bill that raises the thresholds at which the lowest two tax rates cut in.
Even New Zealand First supported it on the basis that some improvement to income is better than none.
It wasn't calculated genius by National. The Greens' move surprised everyone, Labour included.
Labour's finance spokesman, Grant Robertson, didn't know until I told him, although that was apparently just a communications glitch. Someone in the Greens had told someone in Labour.
While it may seem of little consequence whether the Greens support or oppose a Budget measure than is going to pass anyway, it is important in the context of the election.
With the election only four months away, the Greens supporting the centre-piece of the National Government's Budget and Labour opposing it is an entirely different context.
It undermines the carefully crafted measures both Labour and the Greens have struck to co-operate where they can and to gain the confidence of voters.
The code of Budget Responsibility Rules were agreed between them only in March.
It sets some parameters of how they would operate in a coalition Government essentially to give voters they would run orthodox fiscal policy such as getting net core Crown debt to 20 per cent of gdp, just two years later than National; maintaining core Crown spending at 30 per cent of gdp; maintaining surpluses except in a crisis; and supporting a progressive taxation system that is fair, balanced and promotes the long-term sustainability and productivity of the economy.
The code built on the memorandum of understanding a year ago that set out how the two parties would co-operate to get National out of office.
Labour and the Greens would have been better to have both supported it or both oppose National's Budget measure instead of looking divided.
Instead the Greens' caucus decided to support it on the basis that, flawed though it is, it improves the lives of some people that matter to them.
It was not designed to send some subtle message that it is open to dealing with National post election. But it does make you think.
The MOU expires the day after the election on September 23, a clause which has always been seen as a way for Labour to go into coalition without the Greens if that is what New Zealand First demanded.
That also leaves the Greens free to go into coalition with National.
The very thought of it is likely to turn many of the Greens a shade of purple and any suggestion of it would be instantly dismissed.
But post-election, if the Greens are again expected to prop up a Labour-New Zealand First Government on confidence and supply - and face the prospect of completing 24 years outside Government by 2020 - then it has the freedom to contemplate alternatives.
National has been making hay in the House over the Green's support for the tax package but in actual fact, it is the Labour Party that has taken a departure from past practice.
The most similar comparator, the bill in the 2015 Budget that increased social welfare benefits to some beneficiaries, was supported by both the Greens and Labour despite them identifying flaws.
"Labour will support it because doing something is better than doing nothing," Sue Moroney said at the time.
Labour was caught between a rock and a hard place this time. It had a fast decision to make on Thursday whether to make National look good by supporting its bill or risk making itself look bad by opposing something that improves lives.
Journalists get three and a half hours to read the Budget and prepare for it release at 2 pm.
Opposition parties get one hour to respond to a document the Government has been planning for six months.
Leaders and advisers are crammed together in a room in Parliament House having to absorb the content of the Budget which this year was a highly technical blend of measures in the family incomes package.
Adjustments have to be made to pre-written leaders' speech to take account of the Budget reality, and they decide what to support and what not to in the urgency that usually follows.
Given those circumstance, it is perhaps understandable that Andrew Little's response to Steven Joyce appeared so inadequate - although Winston Peters seemed to manage all right under the same time constraints.
I recently watched the Australian Budget on Sky and it is one of the things Australians do better than Kiwis.
The Treasurer delivered it on a Tuesday night, then the Leader of the Opposition gets a full two days to absorb the details and deliver a considered response.
Bill English followed Little in a remarkably confident speech that accentuated the already lop-sided match between them.
This week appears to mark a new phase of English's leadership. After six months of putting himself largely above the fray of political street fighting, while he settles into the job, he took off the gloves and has been on Labour's case every day - mainly over its opposition to some housing developments in Auckland.
English also turned Labour's refrain of "nine long years of Government" on its head, demanding to know what Labour was presenting to the public after "nine long years in Opposition."
The family income package presents a challenge for Labour because it has to come up with an incomes package quickly.
It has to do so in a way that does not disappoint too many voters who will already have mentally banked the promised gains in the Budget to 2.1 million income-earners, superannuitants and students. If they do disappoint, the Greens and New Zealand First are standing by.
The Budget has given National a huge advantage in the build-up to the election campaign and turned up the pressure on Labour.