Of course, in case of need, the Fed, as a lender of last resort, can always relapse into mindless quantitative easing routines — but that would again be a desperate measure of a seemingly never-ending crisis management. Markets, however, would be unlikely to greet with enthusiasm such a repeat performance.

The fiscal policy lever is even more impaired. That is quite obvious from a gross public debt of $22 trillion (107 percent of GDP), and counting, and a public sector budget deficit currently estimated at about 6 percent of GDP.

The latest data, released last Thursday, are pointing to a worsening trend of public finances. In the course of November, federal spending shot up 18 percent from the year earlier while revenues fell 1 percent — in spite of relatively strong economic activity. For the first two months of the present fiscal year, the federal budget deficit soared 51 percent from the same period of 2017, and was running at a mind-boggling annual rate of $1.8 trillion.

How, under those circumstances, can anybody expect that the financial markets could digest such a huge public sector borrowing requirement without causing considerable damage to asset prices?

There are no easy solutions to that predicament, but a rapidly improving U.S. trade balance could go a long way toward preventing a major economic slowdown and providing some support to stretched market valuations.

Here are a few numbers to show where the U.S. stands on that now.

This year, the deficit on American foreign trade in goods and services is expected to take out of the economy more than $550 billion, or 2.7 percent of GDP.

Goods trade alone is considerably worse. In the first 10 months of this year, the U.S. ran a $623 billion trade deficit with China, Europe and Japan. That amount represents 84 percent of the total gap on American international goods transactions.