The stock market selloff may be a vote of no confidence in Bernanke and whoever follows him into the Fed chair next year.
If you think the Fed will taper faster than the economy grows, then a dip in equities is justified. A mistaken confidence in the strength of the economy by policymakers can easily become a drag—especially if you think policymakers are likely to stick to their rosy views in the face of contrary evidence.
So what about bonds? They've also taken a massive hit. Here the picture is even less clear. In one sense, this is what you would expect. Bond yields take their cues from the expected path of future policy rates. The announcement that the Fed expects the end of QE next summer at least puts higher rates as a realistic possibility for, perhaps, 2015.
On the other hand, those who think the Fed is wrong about the strength of the economy should believe that rates will stay lower for longer. That is, they should be buying bonds on the dips. Unless, like those selling stocks, they believe the Fed will tighten too early—raising rates or paring back QE in the face of an economy that is actually still weak. Again, it's a vote of no confidence in the Fed.
Finally, there's the question of what I'll call the Krugman Crank. Paul Krugman has forcibly argued for the view that the Fed's best—perhaps only—tool when interest rates are the zero bound is shaping expectations.
If the Fed can convince markets that it will keep turning the money crank even after the economy recovers, to the point of allowing inflation to rise beyond the usual target, it can encourage demand growth, Krugman contends.
The key to this, however, is that the Fed must credibly promise to be irresponsible. If the market does not believe the Fed will be irresponsible when it comes to inflation, the expectations channel breaks down.
What we may be seeing Thursday is the perception that the Krugman Crank is broken—that the market no longer believes the Fed can credibly promise to be irresponsible. Which means that Fed policy becomes ineffective at the zero bound. So that even if the Fed did react appropriately to a slumping economy by refusing to taper as planned, it might not make a difference.
I'm sorry that so much of this depends on the central bank trying to control—or losing control—of what markets expect. Even worse, it depends on whether markets expect that the Fed can control what the market expects. The image of mirrors staring into mirrors comes to mind. But that is simply the world we live in.
Of course, it's still early days. We don't know how deep the selloff will go, or how long it will run. Perhaps the post-FOMC market moves will just be a blip. Sometimes a roil is just a roil.