They are, of course, asking the impossible, because the Fed itself does not know. And when the Fed says, as it did last week, that its next policy change will depend on employment and price inflation, the statement is branded as bland and useless. But how can it be anything else when the Fed – like all the short-term forecasters – is searching for evidence relevant to its policy decisions?
Fear wrong policies, not America's secular stagnation
Curiously coinciding with the Fed's annual conference is a revival of the declinist debate asserting that the U.S. economy is structurally in an irretrievable stagnation.
Under these conditions, the declinists argue, the monetary policy cannot lift the economy and keep it on a steady and sustainable growth path. And there is worse, they warn: Instead of creating economic growth, the monetary stimulus then just creates all sorts of bubbles, leading to financial crises and further declines in the effectiveness of easy credit policies.
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But all is not lost. Some of the purveyors of the idea of America's secular stagnation suggest that the government may be able to restore the ability of the monetary policy to help create more output and employment.
There is no policy blueprint here, but the reference to government policies clearly implies that taxes, public spending and regulatory changes can be used to increase the economy's growth potential through better infrastructure, competitive markets and a more qualified and efficient labor force.
In other words, what is needed is a better balance and coordination between monetary and fiscal policies.
That is what has been missing in the U.S. for some time. Indeed, the expansionary monetary policy has been working against a sharply restrictive fiscal stance that saw budget deficits declining from 11 percent of gross domestic product (GDP) in 2009 to less than 3 percent this year.
Read MoreYellen: Getting closer to Fed objectives, but still hard to gauge labor market slack
As far as I could see, the Fed had nothing to say about that last week.
ECB wants growth-oriented fiscal policies
But the European Central Bank (ECB) did. In remarks at the Fed's Jackson Hole symposium, the ECB's President Mario Draghi reminded the euro area governments of what they could (and should) do individually, and as a group, to stimulate the economic growth and employment creation.
And that was not the usual exercise where the central bank passes the buck to the government.
With the euro area economy stagnating in the first half of this year, Mr. Draghi restated the ECB's readiness to introduce further measures of monetary stimulation, but he also invited the governments to support their domestic demand through growth-oriented fiscal policies while remaining within the agreed budgetary limits. This politically coded message implies tax cuts with declining public spending; it also refers to structural reforms to create more efficient public services and more flexible labor and product markets.