ONE day, the Federal Reserve will learn, maybe. America's central bank has been preparing markets for months for drawdowns in its programme of stimulative asset purchases, despite criticism that such a "tapering" was premature amid weak employment growth and below-target inflation. Some reckoned the Fed might begin tapering at its next meeting, on the 17-18 of this month. New labour market figures may threaten those plans. America's economy added just 169,000 jobs in August, according to a first estimate released today: below the 184,000 job monthly average of the past 12 months. Worse, gains for the previous two months were revised down by a total of 74,000 jobs. The economy managed its worst employment growth performance in the three months to August since the last August, before the ongoing asset-purchase plan was announced.

Bond yields and the dollar moved down on the news, potentially signalling less market confidence that tapering would be forthcoming. Yet the Fed may go ahead with the drawdown anyway. On the one hand, not all labour market data have been quite this disappointing. Initial jobless claims, for instance, have looked reasonably healthy in recent weeks. And on the other, today's jobs figures did show continued progress on one of the key thresholds identified by the Fed as a guide to its tapering schedule. In remarks after the Fed's June meeting chairman Ben Bernanke suggested that purchases would be wound down so as to end the programme completely around the time the unemployment rate fell to 7.0%. At the time, the rate was 7.6%. In today's report unemployment was down to 7.3%. The 7.0% number was given as a guide rather than a trigger, but the Federal Open Market Committee may feel that failure to rein in purchases at all so close to the advertised target might hurt its credibility.

Doves will surely point out that the drop in the unemployment rate in August was due (as it so often has been in this recovery) to falling labour-force participation. At 63.2%, the labour-force participation rate is at its lowest level of the business cycle: indeed, at the lowest level since 1978. Hawks on the FOMC may then respond that the economy is clearly undergoing serious structural changes and probably doesn't have that much surplus labour. That seems a very difficult argument to support. Earnings have hardly budged over the past year; if the economy were approaching its maximum employment level one would expect to see much more upward pressure on wages.

That debate aside, this was a predictable outcome. It fits the recovery pattern to a tee. In early 2010, the Fed allowed its first round of asset purchases to come to an end and its balance sheet began to shrink. Inflation expectations promptly tanked, forcing the Fed to embark on QE2 in late 2010. That programme was also allowed to end, in the summer of 2011. Inflation expectations and hiring sank again. And so in the fall of 2011 we got "Operation Twist" a QE variant designed to mimic QE's stimulative effects without expanding the balance sheet. That didn't quite do the trick and so in September of 2012 the Fed began buying mortgage-backed securities. In December it tacked on additional and ongoing purchases of Treasury securities as well. There was no set endpoint on that round of purchases, dubbed QE3, and some of us were hopeful that the Fed finally grokked the pattern.

Alas, they had not. No sooner had the American economy gotten a few decent months of job growth under its belt did FOMC members begin calling for a timetable for ending purchases. Inflation expectations began to drop steadily around March. And from May, when the timetable began to come into focus, interest rates began to jump. From the spring, the real interest rate on American government debt is up nearly 2 full percentage points. Unsurprisingly, the economy has begun to sputter.

It is painfully obvious that the Fed dislikes having to deploy unconventional policy and wants to stop using it as soon as possible. One of these days it will realise that the best way to get off and stay off unconventional policy is to push forward with it until the economy is back to full employment and inflation pressures are firm enough to justify interest-rate rises. If you don't kick the ball past the crest of the hill, it just rolls back down and you have to kick it again. Sadly, it may fall to Mr Bernanke's successor, and early 2014, to give the economy the boot it really needs.