Picture this. You are a General in the field making decisions about troop numbers. The President has stated publicly that we need to win this war. You know you need another 200,000 troops or so, maybe more, to win the war. You also know it would be politically inconvenient to make such a request. It would be politically embarrassing for the President to request such a large number of troops even though you, as a general, know that's what it will take. So instead you ask for 30,000 troops because you know that is a palatable number.
Generals know they have to testify before congress to justify their strategic decisions. The President is their commander-in-chief. It's natural to want to be loyal to their commander-in-chief. Therefore, it seems logical that they may even be hesitant to be completely open with the President when making recommendations.
This is the damage too much political interfere can do. Oversight is necessary but politics is a messy business and political interference is dangerous.
Anyone who has seen Ben Bernanke speak about the economy can see he knows what he is talking about. He probably knows monetary policy as well as if not better than anyone else in the country. The theory may not be perfect. But would we rather have a bus driver or a monetary policy expert make the decisions right now? Bus drivers can get elected to congress if they have the gift of the gab.
What we have now are politicians trashing Mr. Bernanke because they think they are tapping into populist rage.
The real populist rage will be directed at these politicians when people realize what they have been doing. This is an effective weapon the other party can use to vote the current majority out of power. Don't play with fire unless you want to get burned.