Race and gender will decide South Carolina - Bill Clinton

Dillon, South Carolina: Former President Bill Clinton suggested that his wife may lose tomorrow's Democratic presidential primary because many black voters will side with Barack Obama.

Republicans, meanwhile, looked to Florida, where a closely-fought race could help anoint the front-runner for the party's presidential nomination.

The former president's unusually direct comment on Wednesday on the possible role of race in the election was in keeping with the Clintons' bid to portray Obama, who is aiming to become the first black US president, as the clear favourite, thereby lessening the potential fallout if Hillary Clinton does not win in South Carolina.

The race for the Democratic presidential nomination has essentially been dominated by New Hampshire primary winner Clinton and Obama, who secured the coveted win the lead-off Iowa caucuses. Stuck in third place was former North Carolina senator John Edwards, a former vice-presidential candidate whose White House bid has been overshadowed by the personality-driven campaigns of his rivals.

Outburst

Voting for president along racial and gender lines "is understandable, because people are proud when someone who they identify with emerges for the first time," Bill Clinton told a Charleston audience on Wednesday while campaigning for his wife, a role he has played all week.

His comments and later outburst came on a day when Obama continued to challenge Hillary Clinton's candour and trustworthiness.