In San Diego meeting, the "UK's Greenspan", Mervyn King gave the Ely Lecture. Excerpt:

The core of the monetary policy problem is uncertainty about future collective decisions resulting from the impossibility and the undesirability of committing our successors to any given monetary policy strategy. The first stems from the fact that is is impossible to commit to future collective decisions; the second reflects the fact that we cannot articulate all possible future states of the world.... The relevant theoretical framework could be described as "public goods meet incomplete contracts"... [all emphasis are Mervyn's] So the ideal is a framework that will implement what we currently believe to be the optimal monetary policy strategy and will deviate from that only if collectively we change our view about what the strategy should be.. [my emphasis]

King's speech gives a clear exposition of what is known as commitment/credibility problem in monetary textbooks. He drew some real examples using the cases of Brazil and UK (credibility problem), Iraq (the role of expectation), and Japan (institutional arrangement did not match economics). Worth reading. Thanks to Dave Warsh who brought this to my attention.