The main argument against a balanced budget amendment is that it makes it more difficult to engage in Keynesian counter-cyclical fiscal policy. The main argument in favor is that without some legal or moral constraint, the ordinary rules of politics will push costs onto unrepresented and unorganized future taxpayers, as Jim Buchanan argued. In order to transcend these arguments I propose an unbalanced budget amendment.
The unbalanced budget amendment is a requirement that in good times the government must run a budget surplus. The virtues of such a rule are that it allows for counter-cylical fiscal policy during a recession. Indeed, it reduces the cost of counter-cyclical fiscal policy because it guarantees a reserve fund for just such emergencies. The unBBA is thus a type of automatic stabilizer of the kind I have argued for before (e.g. here).
A simple version of the unBBA requires surpluses but more generally the rule would be a surplus or a similarly sized reduction from the previous year’s deficit. The size of the required surplus/deficit reduction would be tied to a function of current and recent GDP growth rates.
Notice that while making counter-cyclical fiscal policy easier the unBBA would tend to create budget balance as surpluses in good times were spent in bad times. Thus over a period of time the unBBA has similar results to a BBA. By requiring surpluses (and thus taxes) to be high(er) in good times,however, rather in bad times the unBBA has a lower cost and a better chance of being passed than the BBA.
Overall, an unbalanced budget amendment seems much preferable to a balanced budget amendment.