By Matthew Davis
BBC News, Washington
The United States' First Lady Laura Bush has told the BBC that the "war on terror" has made her job more challenging than she ever anticipated.
"Obviously we didn't expect what happened on September 11th, we never expected we would be in a war, and that is very, very difficult," she said.
Mrs Bush, just back from Africa, made the comments during an interview with the BBC's Sir David Frost.
She also backed the US focus on sexual abstinence in its HIV/Aids relief work.
'Everyone is anti-war'
While her husband struggles in the polls, Mrs Bush's stock has scarcely been higher.
Such is her popularity that some have speculated that she might follow in the footsteps of her predecessor as First Lady, now-Senator Hillary Clinton, and seek elected office.
In a speech on Thursday President George W Bush said his wife would never run for office, and Mrs Bush confirmed it was "absolutely unlikely".
She also said that her friend, US Secretary of State Condoleezza Rice - who despite her denials is still being tipped as a potential 2008 presidential candidate - had "fully decided" not to run.
Mrs Bush spoke instead of the challenge of being a first lady in a country divided by the war in Iraq.
Mrs Bush has just returned from a visit to Liberia, Ghana and Nigeria
"I watched people that I love very much in this job - my mother-in-law and my father-in-law - and I had a real idea of the weight of it, the weight of the job.
"I remember during the Gulf War when President Bush, my husband's father, was president, and the very start of it when the body bags went over to Kuwait - and the whole worry of that, the whole gravity of that.
"The choices that a president makes, for instance, are so consequential, there are so many consequences - and so I knew that, even though that doesn't always help when you are in the midst of it yourself.
"Many people are very, very sincerely anti-war, everyone is anti-war, the president is anti-war, no-one wants war, but no-one wanted what happened on September 11 either."
Abstinence 'a real choice'
Mrs Bush said she had been "moved" by her recent visit to Liberia, Ghana and Nigeria, where she met regional leaders and saw how US funds were being spent on education and HIV/Aids prevention projects.
She rejected criticism that the US attaches moral strings to some financial support for Aids treatment projects, and that it undermines some aspects of prevention.
"It is very important to talk about abstinence, especially in countries where girls feel they have to comply with the wishes of men," she said.
"It sort of irritates me when I hear people act like abstinence is not a real choice because it is, and it is 100% effective."
In the homespun way that has endeared her to the US public, the first lady also revealed what first attracted her to Mr Bush.
"One of the first things I liked about him when I met him was his sense of humour," she said.
"And to be married to someone who can be funny at the dinner table - we had two teenage girls at the dinner table - it was really very nice, he was always able to defuse moments of tension when 13-year-old girls are acting like 13-year-old girls - he's a really wonderful father to our girls."
You can watch the full Laura Bush interview on BBC World on Saturday 21 January at 0630 GMT and 1930 GMT, and on Sunday at 0230 GMT and 1130 GMT.
It will air on BBC News 24 on Saturday 21 January at 1030 GMT, 1530 GMT, 2230 GMT and on Sunday at 0330 GMT.