Mr Osborne's prescription
Usually politicians wait to be in power before laying out their vision in the annual Mais Lecture at Cass Business School. Geoffrey Howe did it in 1981. Lord Lawson in 1984. Gordon Brown in 1999.
Tony Blair was the great exception - he was invited in 1995. Last night it was George Osborne who decided to tempt fate, playing the chancellor-in-waiting with his vision of economic policy if he wins No 11.
Some will detect the whiff of hubris. But there are plenty in the city who call him a lightweight. This speech was supposed to shut them up.
It probably won't, though, as you can see in my piece for the television bulletins tonight, the city economists and grandees I spoke to afterwards seemed pleasantly surprised.
However, this lecture might quiet those who say the Conservatives are about austerity for austerity's sake.
There wasn't much new policy. We heard a bit more about the independent Office of Budget Responsibility, and a commitment to a full "audit" of the public finances, before the first budget, within weeks of a Conservative victory.
Incidentally, the need for that great "opening of the books" - with all the appropriate gasps of horror- means the party won't be able to provide much more detail of its spending plans until after the election. Shame.
Labour and the Liberal Democrats were already criticising the lack of detail before Osborne stood up. But the speech did add intellectual fibre to the slogans, and give a further sense of what Chancellor Osborne's priorities would be.
You can summarise it in three words: It's Mostly Fiscal.
Yes, Osborne talked about monetary and financial policy in his speech: there was a promise not to let Britain inflate its way out of trouble; talk of tweaking the inflation target to take account of housing costs; and a restatement of the case for putting the Bank of England in charge of more nuanced macro and micro prudential regulation of the financial sector.
He also talked about "where the growth would come from" under a Conservative government, re-stating his eight benchmarks for measuring its economic success. But that was the shortest part of the speech. Also the weakest.
And even then, talking about the supply side, and boosting private investment, Mr Osborne could not help talking about the need to raise public sector productivity through a "radical programme of public sector reform".
The beating intellectual heart of the speech was the Osborne's desire to make the strongest - most unapologetic - case he could for tackling the deficit as soon as possible.
Regardless of what you think about the merits of his argument, he made it well.
If you think the Conservatives are right about cutting the deficit as quickly as possible, but you're having trouble convincing your friends - you should read this speech.
If you think that Conservative talk of austerity is all about cutting the government down to size, with little thought for the health of the recovery - you should also read it.
The case for cuts that is given in this speech is more nuanced than that given in the economists' letter in the Sunday Times. It is certainly more thoughtful than anything we've heard previously on this subject from the shadow chancellor.
It is also, largely, an argument about what will best support a vigorous private sector recovery in the next few years (though of course he wants to change the way government works as well).
You might still vigorously disagree with him - and many economists will. But you can't say he hasn't thought about it. Or considered the implications for growth.
People who think that Mr Osborne is over-doing the risks of inaction will quibble with his claim that higher gilt yields show Britain's declining fiscal credibility.
He notes that the spread between ten year gilts and German bunds is now 90 basis points, "compared to 70 basis points for Spain and 110 basis points for Portugal".
But there's a lot going on in that gap: like the fact that we have higher inflation than they do. Also, investors might be expecting faster growth in the UK than in Spain in Portugal, meaning higher medium-term interest rates.
The spreads on sovereign Credit Default Swaps (CDS) - loosely, the cost of insuring against a sovereign default - are a better, albeit imperfect guide to investors' worries. On that measure, the five year spread for the UK is 88 basis points, versus 44 for Germany.
That's not great, but it compares with nearly 170 basis points for Portugal and 127 basis points for Spain.
Of course, you could argue that investors simply think that we will inflate away our debt - making formal default less likely than these other economies who lack that way out. The point is that these market signals are more complicated than they look.
Critics might also say Mr Osborne was under-stating the importance of economic growth in sustaining market confidence.
In his speech he said that people who worried that private demand was too weak to take the place of public spending failed to ask why private demand was weak, and underestimated the role of confidence in supporting growth.
That could be right. But it's also true that, if demand doesn't materialise, sooner or later the markets will punish you for having bleak economic prospects as well.
It is, indeed, all in the timing. And no-one - on either side of this debate - knows what the right timing will turn out to be.
Finally, there is that big hole at the centre of the argument, where the numbers have to go.
However rigorous the argument for early cuts, you're still left wondering, as a practical matter, how George Osborne could make cuts that were large enough to impress the markets - yet small enough to keep the recovery on track.
Even if he could cut a swathe through Whitehall in a matter of weeks (which he can't), Mr Osborne admits there isn't much room for monetary policy to take up the slack.
That will be the unending debate of the next few weeks and months. What you can say tonight about the shadow chancellor is that he has set out his intellectual stall.