It has been leaked that Barack Obama will soon nominate Hillary Clinton – who just months ago berated his policy of opening talks with Iran as “irresponsible and, frankly, naive” – to serve as his secretary of state. When American presidents bring arch-rivals into their service, the fallout can be fateful. The US arguably owes its possession of Alaska to Abraham Lincoln’s choice of William Seward as secretary of state, and its Medicare and Medicaid entitlements to John F. Kennedy’s choice of Lyndon Johnson as vice-president. Ronald Reagan offers the closest parallel to Mr Obama’s expected move. After his insurgency won the primary in 1980, Reagan reached out to the very political establishment he had trounced and discredited. The consequences of his vice-presidential choice – George H. W. Bush, who had ridiculed Reagan’s domestic policy as “voodoo economics” – reverberate even today.

Many bloggers, noting the heavy representation of Clinton administration veterans among Mr Obama’s nominees, complain that he has abandoned his message of change. This is foolish. Bill Clinton is the only other Democrat to have been elected president since the 1970s. Any non-geriatric Democrat with executive-branch experience will be a veteran of his administration. “Understand where the vision for change comes from first and foremost,” Mr Obama said this week in Chicago. “It comes from me.” Right on. The prospect of Mrs Clinton’s ascent pleases 66 per cent of Americans, according to an ABC poll. The nomination makes Mr Obama look strong, not weak.