In fact, a fiscal expansion could actually have a crowding-in effect through an increase in inflation, and inflation expectations, and thereby a reduction in the real interest rate. So people are going to spend more because they expect prices to increase in the future, rather than to spend less because government spending raises interest rates.
While in some jurisdictions, the establishing mandate requires a square focus on inflation, elsewhere other goals are formally set out. The US Federal Reserve Act stipulates these as maximum employment, stable prices and moderate longterm interest rates. Economic development objectives are also sometimes explicitly stated, or at times a more general formulation is provided; sometimes, potentially conflicting objectives appear side by side2.