How much of an ability does the president have to move spending around in the budget?

[bluestateguy]

This is an honest question, not a commentary.

I know that some state governors can move spending around in their state budgets once it is approved by the state legislature. My question is what ability does the president have to move items and spending around in the US budget once it has already been approved by Congress. That is, can the president spend money for one program or agency that has not been appropriated by taking money that has been appropriated to another program or government agency?

And what tools does Congress have if any to stop him from doing so?

[truedelphi]

1. Did we get ourselves a different President?

Barack Obama said in August of 2009 that he couldn't be commenting on the particulars of legislation regarding the Health Care "Reform" Act, as that is Congress' job. Separation of Powers and all that.

But now he can decide the particulars about the major aspects of the way that our budgets will be handled for the next five to ten years?