For $48 billion you would think you could buy the right to pick the Afghan Interior Minister. Or the Governor of Helmand province. Or, come to that, the President’s pledge that he would fight a clean election. One mystery in America’s struggles in Afghanistan is the failure to put real pressure on Hamid Karzai to act in a way that might command popular respect and give the coalition strategy a chance of success.

If you are putting that much into a country — $38 billion (£23 billion) in aid since 2001 and $10 billion planned for 2010, according to the Congressional Research Service — you have a reason to ask for co-operation. That is before counting the 68,000 US troops within the coalition, without which Karzai would likely not be President. There is, too, the chance that more will follow, although senior voices in President Obama’s team are cautioning against sending “the full McChrystal”, the 40,000 extra that General Stanley McChrystal asked for.

The deliberate respectfulness of the US, to the point of diffidence, is sounding tougher. One sign of new pressure was Karzai’s furious acceptance two weeks ago that to claim legitimacy he must consent to a second round of elections. So, too, without contradiction, is the cancellation of the run-off once his challenger withdrew. It suits the US as well; as one official put it: “Why should we bother with all the risk when it’s clear the winner’s going to be the guy in the furry hat?”

The real test comes now: whether the Cabinet includes Abdullah Abdullah, Karzai’s challenger, as well as trustworthy ministers for interior and defence and a Helmand governor who does not obstruct military efforts.

There is no point calling for a cleaner government. This year has been a chronicle of rows with Karzai on just that theme. The details of how Joe Biden, the US Vice-President, and Richard Holbrooke, regional special envoy, erupted with the Afghan leader have become the talk of Kabul.

There is no mystery as to why Karzai does not want to respond; his power has been based on patronage. His Government has become more aware that Afghanistan is rich in resources and so the leverage of US cash may be diminishing. The sale to China of rights at a copper mine, a deal in which Karzai’s brother was instrumental, shows the billions available.

However, it is fair to ask whether the US has been too delicate in dealing with some leaders — more aware of its need of them than it is of their need of help.

It is astounding that the US, despite billions of dollars in aid to Pakistan after the September 11 attacks, failed to secure a single interview with A. Q. Khan, the nuclear scientist responsible for Iran’s nuclear work and other problems that top Obama’s agenda.

You might add to the list Hillary Clinton’s restraint yesterday in regretting that Israel had not gone farther towards “our preference” of a total freeze on West Bank settlements after months of insisting on just that.

Dollars cannot buy honesty. But the US might try harder to see if they could buy co-operation. Obama’s best card against Karzai may be that he will send nothing more without signs that he has a reliable partner in Kabul.

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