By Kim Ghattas
BBC state department correspondent, Kabul
US Secretary of State Hillary Clinton, a political survivor who has repeatedly reinvented herself, used her visit to Kabul to appeal to Hamid Karzai - a leader whose image lies in tatters - to seize a window of opportunity and in essence reinvent himself by seriously tackling the corruption that plagues Afghanistan.
Mr Karzai and Mrs Clinton spent 90 minutes talking one-on-one
"I think that it is clear that he really has turned his attention in a very focused way to what his legacy will be," Mrs Clinton said in a BBC interview after Mr Karzai's inauguration.
"He and his family have given 300 years of service to Afghanistan. He's a real patriot and he wants to be the leader who has ushered Afghanistan in the modern age into a secure democratic future. Sometime it's easier to say that than to do it."
Mrs Clinton struck a positive note and gave the impression that Mr Karzai could rise to the occasion.
Whether she truly believes it is a different thing, but her approach appears to indicate she feels that public hectoring will not yield the best results.
Instead, her approach is a combination of cajoling and friendly pep talks, firm but friendly public stances on corruption - a gamble that could pay off if Mr Karzai decides he wants to burnish his legacy.
Mrs Clinton is in a good position to do so because she has good relations with Mr Karzai. A number of US officials have had stormy exchanges with the Afghan leader, complicating the relationship.
In a sign of how much Mr Karzai values his rapport with a woman who is not only America's top diplomat but also a world celebrity, he reportedly moved up the inauguration date several weeks to accommodate her travel schedule and make sure she could attend.
"The secretary and [Mr Karzai] have a very good relationship, they can speak as politicians and they can talk in terms of not just the policy dimension of things but also the political ramifications," said a senior US official travelling with Mrs Clinton.
Mrs Clinton had dinner with Mr Karzai and some of his ministers on the eve of his inauguration. She then spent 90 minutes talking to him one-on-one.
"She was making the case that for him all those things are not just good policy - they're smart politics, both in the long-term and-short term," added the official.
Few people believe that Mr Karzai is a changed man and he certainly did not appear humbled by the experience of the chaotic process of an election mired by fraud.
Hillary Clinton is emerging as possibly the only person that Mr Karzai is willing to listen to
But all the foreign ministers attending the inauguration seemed to attempt to strike the same positive tone, seeking to encourage Mr Karzai and give him the benefit of doubt in the hope it might make a difference.
It is an approach that is partly dictated by the fact that Washington and its Nato allies have no other choice but to deal with the facts on the ground - and this includes Mr Karzai, as president, regardless of misgivings about him or questions surrounding the legitimacy of his presidency.
And to get Mr Karzai to work with them, it will be essential to coax him.
Any leverage that can be used against Mr Karzai - such as withdrawing troops or withholding aid - is a doubled-edged sword that Washington will have to use very cautiously, if at all, because it could undermine the Obama administration's strategy in Afghanistan.
But US officials also said that if Mr Karzai did the job right then Washington would be generous with aid for Afghanistan, even after the day America starting withdrawing.
'Not always consistent'
Nato countries have demanded that Mr Karzai tackle corruption and the illicit drug trade.
US President Barack Obama has urged him to set up an anti-corruption commission and hold officials accountable.
Mrs Clinton says both Nato and the Afghan leaders must do better
Mr Karzai made some of the right noises in his inauguration speech, though the specific are yet to come.
But Mrs Clinton also said it was important for Nato allies to do a better job and co-ordinate their military and civilian strategy, saying it was not only about making demands on Afghanistan.
Observers point out acknowledging that there is work to be done by both parties, instead of only admonishing the Afghan government, could help bring Mr Karzai round to seeing his own failures and hopefully addressing them.
"Mr Karzai and the secretary share the view that over the past year we have not always been the most consistent partners," said the senior official, adding that there were "legitimate questions about how effectively we are helping them to help themselves".
Mrs Clinton, who has spoken to Mr Karzai several times about her own experiences as a politician, said: "I've always tried to listen to him to hear what's really on his mind, his concerns, how he views the problems he faces, and then to be responsive but also to offer a perspective that is perhaps useful."
But along with the friendly words and the cajoling, the tough talking continues as well.
In the BBC interview, Mrs Clinton said the Afghans knew there would be consequences if they failed to deliver. Without outlining those consequences, she said this had been made very clear to them.
For the past several months, media reports abounded about Mrs Clinton having been overshadowed by the special envoys she had appointed, including Special Representative for Afghanistan and Pakistan Richard Holbrooke.
But in the light of her trip to Kabul, she is emerging as possibly the only person that Mr Karzai is willing to listen to. It remains to be seen whether he actually feels inclined to do what she tells him.