For the past four years Senator John Kerry has been “the man who lost to George Bush in the 2004 race for the White House”. For most of the past 24 years, he has also been the junior Senator for Massachusetts, overshadowed by Ted Kennedy. But after one exhausting trip to Kabul, he is suddenly much more.

The patrician New Englander with the long face and helmet of grey hair has transformed himself over five days of shuttle diplomacy and, he says, “a thousand cups of tea” into Afghan election saviour, and the Administration’s pointman on President Karzai. He professes embarrassment when spoken of as a de facto Secretary of State, but when he speaks on Afghanistan at the Council on Foreign Relations today, Washington will listen as if he were — and with good reason.

President Obama’s press secretary lavished praised on Mr Kerry at a recent briefing for his depth of “experience and insight” — and then called him “Secretary Kerry” by mistake.

Mr Kerry is not in Mr Obama’s Cabinet, but he might as well be. An unusually vocal chairman of the Senate Committee on Foreign Relations and close ally of Mr Obama, he has, in effect, supplanted Richard Holbrooke, the White House’s special representative to Afghanistan and Pakistan, at a critical point in US negotiations.

His shift from grey eminence to power broker began a week ago. Dining with American generals in Kabul on a long-scheduled visit, he was interrupted by the US Ambassador, with a message that talks with Mr Karzai were breaking down.

Mr Kerry spent hours at the President’s palace that night, more the next afternoon, then flew to Kandahar and back to Kabul for more talks. On Monday he went to Islamabad, then back for yet more talks with Mr Karzai — apparently using reminiscences of his own defeat in 2004 to nudge the President towards a deal.

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