Democratic leaders are becoming increasingly worried about the long-term consequences of the drawn-out and contentious presidential nomination race between Barack Obama and Hillary Clinton. In the past few weeks a number of prominent Democratic elected officials, including Senator Patrick Leahy of Vermont and New Mexico Governor Bill Richardson, have called on Hillary Clinton to consider ending her campaign in the near future on the grounds that by staying in the race she is damaging the party's chances of winning the presidency in November. Pundits and journalists have also argued that the extended nomination battle between Clinton and Obama is allowing...