Government cannot roll over the debt forever (ponzi game is
not allowed). In the long run, inter-temporal budget constraint has to
be satisfied, which is possible either through government spending
adjustment or increasing government revenues. So current budget deficit
calls for adjustment, in the future, in spending or revenues. There are
four hypotheses, in the literature, in this regard: the tax-and-spending
hypothesis, the spending-and-tax hypothesis, bi-directional causality
between government revenues and government expenditures, and
independence of taxes and expenditures hypothesis. The last hypothesis,
however, have negative implications, in the long run, in terms of debt
sustainability and inflation