Will voters opt for Sajid Javid's semi-skimmed or John McDonnell's full cream?
The two most important speeches to date of the election campaign have been made by the Chancellor and Shadow Chancellor, Sajid Javid and John McDonnell, and not by their respective leaders.
And it is just possible these will still be the most important speeches in five weeks time, on polling day.
Because they set out how much each of the big parties would and could spend and invest in the event that either wins wins a majority of seats and could govern without the support of shackles or deals with other parties.
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McDonnell's speech does something more, which ought to make Boris Johnson very anxious indeed.
He makes an explicit promise to transfer money and POWER to the north of England.
This may be hugely important.
Because it creates a dilemma for northern voters who voted to leave the EU and whose votes Johnson desperately needs if he is to regain power on December 12.
McDonnell is saying to northern voters: "If you voted for Brexit because you were tired of being bossed by a so-called London elite, and being starved of investment while southerners slept on mattresses stuffed with cash, well if you cast your vote for Labour, we'll drown you in money for schools, hospitals, trains and windfarms, and we'll relocate important parts of government, including chunks of the Treasury, to towns and cities near you".
It would be odd if this "rebalancing" of political and economic clout to the north wasn't seductive to northern voters - especially since the sums of money involved are non trivial (ahem).
McDonnell is bribing voters with a significant £55 billion a year from 2020 of investment in public services, infrastructure and green industrial re-engineering.
Which is not trivial.
There are begged questions.
Where is the money coming from?
And is this ambition affordable?
It would be borrowed.
And McDonnell would create a new rule that there would be no limit on borrowing for investment, so long as the government's interest costs would not exceed 10% of tax revenue "in normal times" and so long as the value of gross assets created by the investment were to increase faster than the value of the associated debt.
Now what tickles my fancy here is that McDonnell would be importing to the treasury the kind of borrowing and investing rules employed by the private equity firms he would typically regard as casino gamblers.
The point is that the whole history of capitalism shows it is not challenging to come up with a valuation that a railway or a power company or leased properties are worth more than the borrowed money that paid for them, until that is the cash flow dries up and the whole lot go kaput.
But perhaps I am being uncharitable.
So how does the Tories' Javid respond to McDonnell's magnificent bribe to voters?
Well with a bribe of his own.
His is quite a bit smaller, an extra £25 billion a year of investment, within five years.
But he would argue that his £25 billion is sustainable, and therefore more secure.
Even so, the Tories under Javid and Johnson are moving significantly away from the fiscal constraints and austerity of Cameron, Osborne, May and Hammond.
Javid's new fiscal rule would commit only to balancing the budget for current spending, but would allow borrowing of up to 3% of national income to fund investment - and no serious economist thinks there is any prospect of the debt denominator, GDP, growing at 3% a year till Javid’s time in office is ancient history (at the earliest).
Now although he claims otherwise, this would surely see the national debt rise as a share of national income, from its current level of 75% of GDP, or double where it was before the 2008 crash.
So it represents a significant shift away from prudence and austerity.Which takes me - finally - to the politics of all this.
If the swing voter is fabled "Workington man" - the leave supporter vacillating between Johnson and Corbyn - will he, she or they go for McDonnell's big bucks, and signficant devolution of the investment decisions, or Javid's half the money but greater safeguards against a boom induced bust?
Whoever wins the election, Osborne's skimmed milk is being replaced by Javid's semi skimmed and McDonnell's full cream (with more rights for local people to run the dairy and milk the cows).
It is a genuine choice. And actually it may ultimately prove almost as important as how and whether we leave the EU.
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