As Barack Obama struggles to build consensus to reform the nation’s healthcare system, the case of Henry Louis Gates Jr, a respected black Harvard professor arrested by local police in Cambridge, Massachusetts, is an unwelcome distraction. The arrest – and Mr Obama’s ill-considered reaction to it – has fuelled renewed discussion of race in the US.

The basic outline of the case is clear. Mr Gates was arrested following a neighbour’s call to local police who saw two men trying to break into Mr Gates’ home, mistaking the owner for a burglar.