KEY POINTS:
As sure as night follows day, the Prime Minister could count on two things occurring the instant she gave her word that tax cuts will happen under Labour.
She knew National would immediately start trawling through statements, speeches, news clippings and Hansard for anything she might have said about tax cuts which might now embarrass her in the light of her speech to the Labour Party conference.
She would also have been well aware that her assertion that tax cuts had been made possible through the Treasury finally conceding bumper Budget surpluses are here to stay would set off a parallel search for what else officials had told ministers about the feasibility of tax cuts.
So when John Key got up in Parliament yesterday to ask if she still stood by her statement that she would have liked to have cut taxes earlier but never had the advice to make it possible, Helen Clark knew National's leader had something up his sleeve.
She tried to head him off at the pass by being first in raising Treasury's call for tax cuts in its briefing papers after the 2005 election. That suggestion was rejected by Labour because it would have meant money set aside for spending on things such as the abolition of interest on student loans and rates rebates for the elderly would instead have gone on tax cuts.
Given everyone is well aware of that famous piece of advice, Mr Key had to have something better to bolster National's campaign to pigeonhole Labour as a reluctant tax-cutter.
Mr Key did have something - Treasury advice from May 2003 which assured the Government that it could cut taxes without jeopardising the rest of its fiscal objectives.
But this was easily batted away by the Prime Minister, who responded somewhat sarcastically that "the member would recall" that the following year Labour had delivered substantial tax cuts through the Working for Families programme - tax cuts that National had not supported.
Never mind that back in 2004 Labour described Working for Families as targeted family assistance - not "tax cuts". The Prime Minister clearly felt she had the measure of Mr Key to the point that she could crack a joke about National's leader changing his tune so much "that he has difficulty singing in the same key for long".
This was as lame as the last horse in yesterday's Melbourne Cup and got about as much applause. Mr Key was more successful in playing for laughs. He had saved his best shot for last.
In writing her conference speech praising tax cuts, he asked, had she taken any advice from the person who led Labour back in 2000. That person had told Labour's conference that year that tax cuts were a "path to inequality" and "the promises of visionless and intellectually bankrupt people". That person was Helen Clark, of course.
A kind of smile flitted across the Prime Minister's face; the sort of grin-and-bear-it smile of someone who knows how something said in the past can come back to haunt you.
But these were words from long ago. If a week is a long time in politics, something said seven years ago is light years away. Mr Key may have got the better of yesterday's exchange but there are more battles left to win.
