US Secretary of State Hillary Clinton has confirmed she will not serve in Barack Obama's administration if he is re-elected as President next year. In an interview with ABC News on Tuesday she said she would remain in her post after the November election for a short time in order to ensure a "seamless transition" to her successor. She added that she was "confident" Obama would win a second term.

The news will not be welcomed by Obama's campaign team. Clinton commands a huge amount of support among Democratic voters and could have been the perfect running mate for the beleaguered incumbent in his efforts to unify the party's disgruntled activist base. Further, her traditional status as the Republicans favourite liberal hate-figure - a huge factor in her failure to win the Democratic nomination in 2008 - has all but vanished over the last four years as a result of what is widely perceived as a competent and effective performance at the State Department.

Obama will have to think seriously about whether or not he wants Joe Biden, his gaffe-prone Vice President, to join him on the 2012 Democratic ticket. One possible alternative is the highly rated Kathleen Sebelius, the former Governor of Kansas and current Secretary of Health and Human Services.