What's behind Obama's sudden attempt to fire the AmeriCorps inspector general?

There are a number of unanswered questions today about President Obama's abrupt decision to fire the inspector general of the AmeriCorps program... Inspectors General Reform Act... [co-sponsored by] then-Sen Barack Obama... requires the president to outline the cause for his decision to remove an IG. Beyond saying that he did not have the "fullest confidence" in Walpin, Obama gave no reason for his action.... Republican Sen. Charles Grassley... suggests that the White House first tried to muscle Walpin out of his job without having to go through the 30-day process. It was only when Walpin refused to resign that the White House then notified Congress of the president's intention to fire Walpin....