In addition, in the face of massive private sector deleveraging, monetary policy has limited effect, because the economy is likely to have been pushed up against the zero lower bound, where real interest rate is negative but nominal interest rate cannot fall below zero. Some economists, such as Paul Krugman, have argued that in this case, fiscal policy should step in and deficit-financed government spending can, at least in principle, help avoid a sharp rise in unemployment and the pressure of deflation, therefore facilitating the process of private sector deleveraging and reducing the overall damage to the economy. Note that this comes at the expense of higher government debt, which will compromise the overall deleveraging of the economy. This view is in contrast with some other economists, who argue that a problem created by excessive debt cannot be ultimately solved by running up more debt, because unsustainably high government budget deficit could seriously harm the stability and long-run prospect of the economy.