Hillary Clinton, the US Secretary of State, has complained of the tiring natue of her job and said she will step back from the role before the end of Barack Obama's presidency.
Mrs Clinton said she would not serve a full eight years if President Barack Obama is re-elected in 2012. There has been speculation in America that Mrs Clinton could resign to run for the governor's post in New York but she said she wanted to retire to writing and teaching.The former First Lady, who has spent two decades in the national spotlight and narrowly lost her own bid to be president in 2008, said she enjoyed her job as the top US diplomat but found it physically grueling.
Asked if she would serve eight years, she replied: "No, I really can't."
"The whole eight - that would be very challenging," she said in the interview broadcast on television.
"It's a 24-7 job and I think at some point, I will be very happy to pass it on to someone else."
Mrs Clinton repeated that she would not run again for president, saying she wanted a private life.
"There are so many things I'm interested in, really going back to private life and spending time reading and writing and maybe teaching. Maybe some personal travel - not the kind of travel where you bring a couple of hundred people with you," she said.
Mrs Clinton said she also hoped throughout her life to be a strong advocate for the rights of women and girls.
Secretaries of state have rarely served more than one presidential term, although George Shultz was in office for six and a half years under Ronald Reagan.