Federal Reserve Chairman Ben Bernanke must not want to keep the market guessing about monetary policy. In a speech on Friday, he practically announced that the central bank would take action to further loosen monetary policy at its next meeting. His remarks essentially served as an explanation of why the Fed is justified to take such action. At this point, it's really only a question of details.
This sentence, where Bernanke begins his discussion of monetary policy tools, makes the Fed's intentions crystal clear:
Given the Committee's objectives, there would appear--all else being equal--to be a case for further action.
Bernanke refers to the Fed's mandate no less than 13 times in the speech. He stresses that if employment isn't maximized and inflation isn't meeting its target, then the Fed must act. No one would legitimately be able to argue that unemployment isn't a problem right now, so that just leaves inflation.
At this time, deflation hasn't gripped the nation, but inflation is quite low. In fact, Bernanke and the other central bankers think it's too low. Their target is around 2%, while consumer prices inflation has declined to closer to 1% over the past year, as shown quite clearly by the September data released today as Bernanke was speaking.