To an outsider, Timothy Geithner must seem like a jinx. Whenever a big American bank has run into trouble, wherever there is a Wall Street catastrophe, the 48-year-old president of the New York Federal Reserve is in the shadows.

It was Mr Geithner who, sitting alongside Henry Paulson, the US Treasury Secretary, in his vault-like office at the New York Fed, finally realised that Lehman Brothers would go bust. It was Mr Geithner, far more of an expert on capital markets than his boss Ben Bernanke, the Chairman of the Federal Reserve, who helped to devise a nationalisation programme for AIG, with hours to spare before the world's largest insurer collapsed. And last week it was Mr Geithner who acted as referee during a nasty fight between Wells Fargo and Citigroup to carve up the carcass of Wachovia, the retail bank.

Yet the banking crisis could not have come at a better time for Mr Geithner. Tipped in Washington as the next US Treasury Secretary in the event of a win by Barack Obama, he has been shown at his best in a crisis in recent months. He has spent the past year getting his head round credit derivatives, with fortuitous timing.

Timing appears to be speciality. At Dartmouth, the Ivy League university, he studied Government and Asian studies well before learning that Chinese was all the rage. He joined the US Treasury in 1988 and worked in three administrations for five secretaries, giving him far more experience of Capitol Hill than the man he may take over from — Mr Paulson.

Some coo about Mr Geithner's wrinkle-free face and inclusive manner; others find him awkward, a bit nerdy and so lacking in animation that he could ask you on a date in the same tone as declaring you bankrupt. Still, in the event that Mr Geithner does become the next Treasury Secretary, there would be little need for a trial period to get up to speed.