The debt-ceiling talks in Washington have stumbled again. The sticking point, as before, is taxes. Republicans refuse to raise them and Democrats are insisting on it. The drama and the walkouts are part of the show: in all likelihood a deal of some sort will still be struck before the August 2 deadline. Whether it is a good deal for the country is another question.

A good deal means avoiding abrupt fiscal tightening in the short term – a point Federal Reserve chairman Ben Bernanke emphasised last week – while bringing long-term public borrowing under control. These arguments are well understood, even if the country’s politicians are ignoring them. Another topic, though, has received no attention at all. It is at least as important. This is the issue of fiscal capacity.

By this I do not just mean getting public debt back under control. That matters, obviously. To retain counter-cyclical fiscal policy as an option in the next recession, the debt ratio will have to fall. The Congressional Budget Office just estimated?that on unchanged policies, the ratio of public debt to gross domestic product would be 100 per cent by around 2020 and would then rise literally off the chart, making activist fiscal policy impossible. This is the argument for fiscal control that Democrats should have been making all along, and still are not.