It is hard not to feel sympathy for John Snow, whose departure from the Bush administration has been common knowledge in Washington for months. A competent and respected Treasury secretary, Mr Snow has been undermined by the culture of leaks that often accompanies high office. And now, unsurprisingly, it is proving hard to find a replacement.

When George W. Bush came to office in January 2001, it became clear the role of Treasury secretary would be sharply downgraded from the prominence it enjoyed under Bill Clinton. In contrast to finance ministers in parliamentary democracies, US Treasury secretaries already have to share their fiscal and policymaking duties with other officials - particularly the head of the office of management and budget.