developed in Romer (1986, 1987, 1990) and in Lucas (1988). For simplicity
we assume an AK production structure that captures the basic idea of these
models. The microfoundation of individual consumption-saving decisions
is given in an overlapping generations model in the tradition of Diamond
(1965).
With regard to the budget deficit the government is in control of three
instruments; the government purchase ratio, the budget deficit ratio, and
the tax rate. Assume that the purchase ratio is given exogenously. Then, the
government can follow either of two strategies, it fixes the deficit ratio or the
tax rate. If the government fixes the deficit ratio, then according to the budget
constraint the tax rate will be endogenous. And if the government fixes the tax
rate, then the deficit ratio is endogenous. Carlberg (1995) compares these
two strategies in overlapping generation models with neoclassical growth.
Given a fixed deficit ratio there are, in general, two steady states. However,
there is a critical deficit ratio. If the deficit ratio exceeds the critical level,
then there is no steady state. Given a fixed tax rate there is, in general, no
steady state. As an exception, if the future consumption elasticity is very large
and if the primary deficit ratio is extremely small, there will be two steady
states. One of them is stable, the other is unstable. Hence, as a main result, a
fixed deficit ratio is feasible. In contrast, a fixed tax rate is not sustainable.
Saint-Paul (1992) and Josten (2000) analyze public debt in overlapping