An ominous paper by the US Federal Reserve has become the hottest document in high finance.

It was intended to reassure us that the world's hegemonic central bank still has ample firepower to overcome the next downturn. But the author was too honest. He has instead set off an agitated debate, and rattled a lot of nerves.

David Reifschneider's analysis - 'Gauging the Ability of the FOMC to Respond to Future Recessions' - more or less concedes that the Fed has run out of heavy ammunition.

The Federal Open Market Committee had to cut interest rates by an average of 550 basis points over the last nine recessions in order to break the fall and stabilize the economy. It could not possibly do so right now, or next year, or the year after. Quantitative easing (QE) in its current form cannot compensate, and nor can forward guidance. They are largely exhausted in any case.

"One cannot rule out the possibility that there could be circumstances in the future in which the ability of the FOMC to provide the desired degree of accommodation using these tools would be strained," he wrote.

This admission is painfully topical as a plethora of data suggest that the US economy may have hit a brick wall in August. The ISM gauge of manufacturing plunged below the boom-bust line to 49.4, and the services index dropped to a six-year low, with new orders crashing nine points.

My own tentative view is that these ISM readings are rogue surveys. The Atlanta Fed's 'GDPNow' tracker points to robust US growth of 3.6pc in the third quarter. The New York Fed version is coming in at 2.8pc. 

Yet the US expansion is already long in the tooth after 87 months, and late-cycle chemistry is notoriously unpredictable. Warning signs certainly abound. Corporate profits have been slipping for six quarters, the typical precursor to an abrupt slump in business spending. "The only thing keeping the US out of recession is the US consumer. If consumption stalls then we really are in trouble," says Albert Edwards from Societe Generale.

I am willing to bet against him for now. The M1 money supply - often a good leading indicator - has picked up after a weak patch earlier this year and is now surging at a rate of 10.1pc. This pace would normally signal a burst of torrid growth a few months later. It is in stark contrast to the monetary contraction before the Lehman crisis.

My presumption is that the day of reckoning has been pushed well into 2017, but in the dead of the night I have a horrible sweaty feeling that Mr Edwards may be right. It is not a time to be chasing stock markets already at vertiginous levels.

And:

History will judge that those nations best able to weather the next global downturn are those that grasp the essential character of our desperate deflationary age, and can cast aside deeply-ingrained and totemic beliefs about debt. The losers will be those spooked by shadows on the wall.

The winners - or survivors - will be those most willing to seize on the cheapest borrowing costs in history to fight back, preferably combining fiscal and monetary in a radical fashion. Call it helicopter money if you want, or 'overt monetary financing' of deficits. The accounting terminology is irrelevant.

Since no country can risk watching its precious national stimulus leak away to free riders in the austerity camp - at least in a crisis - this may imply some degree of calibrated protectionism. The twin liberal pieties of progressive public policy and global free trade may ultimately come into conflict. That is tomorrow's battle.

David Fuller's view

Yes, the Fed would like a cushion in terms of higher interest rates as a defence for limiting the next recession.  However, we do not live in an economic environment which would make that possible at this time.  Moreover, we can only guess as to when and to what extent circumstances are likely to change in future.  So far, the Fed has wisely held off on raising rates, which could make a soft economy even weaker, particularly if the Dollar Index rose, as it most likely would.

However, it would be mistaken to think that the Fed is in charge of the economy, beyond its role as the regulator of US monetary policy.  The traditional three engines of economic growth are consumer, corporate and government spending. 

Consumer spending is encouraging and has delivered most of the US GDP growth that we are currently seeing.  Corporations remain cautious but could be encouraged to increase spending with tax cuts, including incentives on research and development projects.  Fiscal spending by national and regional governments on necessary infrastructure projects would also help GDP growth, currently and also over the longer term. 

Other countries could do the same.  Yes, budget deficits would increase, at least initially, but stronger GDP growth should then reduce them. 

What about stock markets?  They have done very well, thanks to QE.  However, six consecutive quarters of soft corporate profits in the USA is certainly a concern.  This is not a time to be chasing stock markets already trading at vertiginous levels, as AEP says above.       

Here is a PDF of AEP’s column.