Fiscal policy in the Mundell–Fleming model
Fiscal policy manipulates government spending and taxes to achieve policy goals (such as a rise in income).
Fiscal policy comprises all policy measures related to the government budget. On the aggregate level this amounts to government spending and raising gov- ernment revenue by levying taxes.
In terms of the Mundell–Fleming model, if the government increases expenditures the IS curve shifts to the right. The size of this shift is given by the multiplier derived in Chapter 2 (times G). There the interest rate was (implicitly) considered constant, and the multiplier indicated by how much equilibrium income rises after a one-unit increase of government expenditure. As this holds at all interest rates, the IS curve shifts exactly by the size of the original multiplier to the right (see Figure 5.1).
If the interest rate actually remains at the level of the world interest rate, and the foreign exchange market equilibrium condition says it must, equilib- rium moves from A to B. B is not a money market equilibrium, however. With the interest rate unchanged and higher income than at A, individuals wish to hold more money at B than is being supplied. This excess demand for money puts upward pressure on the interest rate. If we could ignore the FE curve, this would drive up the interest rate along LM1 until it reached equi- librium in the money market at C.