It has become commonplace to say that America’s Hispanic population will increasingly hold the whip hand in US politics. But in the increasingly volatile race for the 2008 Democratic nomination, African-Americans could prove the decisive arbiters.

As the wife of “America’s first black president” – in the words of Toni Morrison, the celebrated writer – Hillary Clinton can draw upon a deep well of African-American loyalty. According to polls that loyalty is holding up in spite of the meteoric rise of Barack Obama – only the third black person to be elected to the US Senate and the first with any serious shot at the White House.