Hillary Clinton’s supporters on Tuesday proclaimed her crushing victory in West Virginia as evidence of Barack Obama’s continuing weakness among blue collar workers. But the simultaneous Democratic victory in a Mississippi congressional race suggested there may be little the Republicans can do to stop 2008 from being a washout.

Fuelled by a strong African-American turnout, the Democratic win in Mississippi on Tuesday delivered the third consecutive Republican congressional defeat in otherwise safe districts following a recent loss in Louisiana and in the Illinois district of Dennis Hastert, the former Republican speaker.