What was John McCain thinking when he suggested delaying his first debate with Barack Obama? There is no way that he comes well out of the suggestion, for all his call for a truce to beat America’s economic woes. If he were eight points ahead in the polls it might seem as statesmanlike as he hoped. But eight points or so behind, it looks weak, and worse, lacking in anything to say.

The pity is that, on the economy, neither candidate knows what he wants to say. They are both taking refuge in the endless and easily invoked terrors of foreign affairs, the subject of tonight’s debate — if it goes ahead.

But while the world wants the next president to be sure-footed and thoughtful about unpleasant dilemmas abroad, the bigger threat to Americans’ daily lives is the faltering economy and precarious financial system. The best way of choosing the next president would be on his detailed answers to those questions; shame that both candidates have ducked it.

Tonight’s confrontation is about foreign policy only because Obama asked for a switch from the original topic, the economy. This, surely, was a mistake. Obama jumped from the issue that put him back in the lead to the one that is McCain’s perceived strength.

That odd request revealed Obama’s uncertainty about whether to back the Bush Administration’s wildly unpopular $700 billion rescue scheme, and beyond that, how to overhaul the US’s antique banking regulation. But McCain then matched that weakness with his own, in his suggestion to replace a debate with a joint plan to tackle the crisis. And Bush tried to co-opt the pair of them in last night’s emergency White House meeting. If there is one area where the two candidates should test their ideas against each other head on, it is this. There are no cheap answers, and so no popular ones, but some are much better than others.

These debates are painful theatre, as each candidate shuffles through his stack of handcrafted ripostes. The promises they make (if any) can be lost in the instant microanalysis of whether they were too overbearing, patronising, intellectual, wooden, long-winded.

In their foreign policy encounter, only a few answers are important. In the rush to be seen not to jeopardise the banking system, the candidates are dodging their responsibility to say what they will do about a problem that is not going to be dispatched this week.

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