When the US economic downturn began, the country's fiscal position was already weak. The administration nonetheless proposed an emergency stimulus - mostly criticised as too miserly. Farther ahead, demographic pressures and the failure to curb rising healthcare costs (which drive up public spending on Medicare and Medicaid) make matters worse. Both presidential candidates are big on avowals of fiscal rectitude, but not on remedies. Their proposals on taxes and spending are quite different but have this much in common: if enacted, they would add mightily to the fiscal problem.

Before the economy slowed, earlier budget forecasts - admittedly unreliable at the best of times - had turned out to be too pessimistic. Revenues had proved more buoyant than expected, and the deficit had shrunk. Thus voters and politicians have come to regard all fiscal gloom as exaggerated. Congress and the administration are expected to voice concern but do nothing, and indeed to spring boldly to the economy's support with emergency tax cuts when demand slumps. Sooner or later, this complacency will have to confront a painful fiscal reality.

In the first eight months of the current fiscal year, the deficit was more than $300bn, roughly $170bn bigger than in the same period last year. Only about $50bn of that deterioration was due to the stimulus tax rebates that began to be paid out this spring (another $50bn or so of those rebates is still in the pipeline). Most of the rest was due not to slowing revenues but to sharply increased spending, with rises across the board.

On the spending side, the future pattern will be the same, only more so. The Congressional Budget Office expects the cost of Medicare to rise from 2.7 per cent of GDP in 2007 to nearly 6 per cent by 2030. Together, Social Security and Medicaid will add another three percentage points. This puts the deficit on track to exceed 10 per cent of GDP by 2030, and 20 per cent by 2050, taking no account of the further increases in spending and new cuts in taxes that both candidates appear to be proposing. This path implies explosive growth in public debt: it is literally unsustainable.

Fiscal consolidation, unappealing though it may be as a platform, ought to be the organising principle for current political debate in the US. The country must start to get a grip on spending, or steel itself to pay very much more in taxes. The electorate and its leaders continue to flinch at facing, let alone making, this choice. It can be evaded between now and November, one supposes - but not indefinitely.