The relationship between public expenditure and aggregate income has long been debated in economic literature. According to Wagner, expenditure is an endogenous factor or an outcome. On the other hand, Keynes considered public expenditure as an exogenous factor to be used as a policy instrument...

To minimize deadweight losses, tax rates should vary unpredictably so agents cannot rearrange their work and consumption habits. As a result, optimally set tax rates will be a nonstationary time series or, put differently, changes in the tax rate will be unpredictable. This paper identifies...