The concept of accountability refers to the legal and political obligation of an independent central bank to justify and explain its decisions to its constituents, finance Ministers, analysts and academics as well as to the citizens and their elected representatives.
Lower rates over the maturity spectrum of public and private securities should strengthen aggregate demand in the usual ways and thus help to end deflation. Of course, if operating in relatively shortdated Treasury debt proved insufficient, the Fed could also attempt to cap yields of Treasury securities at still longer maturities, say three to six years.