This week the Federal Reserve’s Open Market Committee — the group of men and women who set U.S. monetary policy — will be holding its sixth meeting of 2013. At the meeting’s end, the committee is widely expected to announce the so-called “taper” — a slowing of the pace at which it buys long-term assets.

Memo to the Fed: Please don’t do it. True, the arguments for a taper are neither crazy nor stupid, which makes them unusual for current U.S. policy debate. But if you think about the balance of risks, this is a bad time to be doing anything that looks like a tightening of monetary policy.

O.K., what are we talking about here? In normal times, the Fed tries to guide the economy by buying and selling short-term U.S. debt, which effectively lets it control short-term interest rates. Since 2008, however, short-term rates have been near zero, which means that they can’t go lower (since people would just hoard cash instead). Yet the economy has remained weak, so the Fed has tried to gain traction through unconventional measures — mainly by buying longer-term bonds, both U.S. government debt and bonds issued by federally sponsored home-lending agencies.

Now the Fed is talking about slowing the pace of these purchases, bringing them to a complete halt by sometime next year. Why?