It might not be a crisis on the scale of the ongoing war in Iraq, but finding a successor to the disgraced Paul Wolfowitz as head of the World Bank is proving a considerable headache for US President George W. Bush. The bank's new president must fill two roles; most urgently to erase the scandal from an institution tainted by Mr Wolfowitz's resignation over an improper promotion and pay rise for his girlfriend. Equally as important, the new boss must find a way to unite the 185 member nations that are split over the direction of the 63-year-old institution, which provides economic advice and loans to developing nations. Mr Bush, who has asked US Treasury chief Henry Paulson to consult other countries before making a nomination, says he is minded to follow tradition and appoint an American. All 10 previous presidents have come from the US, which is the bank's largest shareholder with a stake of more than 16 per cent. It would disadvantage fancied candidates such as Ashraf Ghani, the former Afghanistan finance minister, and Nigerian Ngozi Okonjo-Iweala, the bank's former vice-president, and sound a flat note for outsiders such as rock star Bono and Tony Blair, the outgoing British Prime Minister. Three Americans, therefore, head a crowded list of possible successors to Mr Wolfowitz, who stands down on June 30. The frontrunners Robert Kimmitt, 59, deputy secretary of US Treasury. Form At last weekend's meeting of G8 finance ministers in Germany, Mr Kimmitt said he was 'flattered' to be linked to the job but insisted it was nothing more than speculation. Yet with two trouble-free years as the Treasury's deputy chief behind him and a long and successful career in public service, he was always going to be considered a leading candidate. The respected former soldier, who won a Purple Heart in Vietnam, also has experience of the World Bank, having served on its panel of arbitrators for investment disputes. After Mr Wolfowitz's often abrasive tenure, Mr Kimmitt's diplomatic skills - he was US ambassador to Germany from 1991 to 1993 - would be welcomed by bank staff, as would his knowledge of global finance gleaned from a four-year spell as a managing director of investment bankers Lehman Brothers in the mid-1990s. Like Mr Wolfowitz, he says he has no tolerance for corruption. Pilfering third-world dictators should note that he was responsible for sending teams of undercover inspectors into Iraq to help staunch the siphoning of public money to insurgents. Prospects While it's an advantage that his boss, Mr Paulson, is leading the search for Mr Wolfowitz's successor, Mr Kimmitt's credentials make him a strong favourite in his own right. His appointment would help appease critics who accuse Mr Bush of promoting unsuitable candidates as a reward for loyalty. Robert Zoellick, 53, former deputy US secretary of state. Form Mr Zoellick has been out of government service since resigning as Condoleezza Rice's deputy in July last year to rejoin the private sector with investment bank Goldman Sachs. But his four years as US trade representative from 2001 to 2005, during which he helped initiate the Doha trade talks and later framed America's policies towards China, make him an attractive candidate. 'Among the Bush insiders, the person who has the most credible CV is Zoellick,' says Ricardo Hausmann, director of the Centre for International studies at Harvard University where Mr Zoellick studied. His experience with global economic issues pre-dates the current White House administration. He filled various roles in the Treasury Department from 1985 to 1988 during Ronald Reagan's presidency and was George H.W. Bush's personal representative at the G7 economic summits in 1991 and 1992. His appointment will be closely watched in China, the country for which he negotiated admission to the World Trade Organisation in 2001 and encouraged to become 'a responsible stakeholder' of world affairs after Sino-US discussions four years later. Prospects He has already been overlooked for the post, when Mr Bush appointed Mr Wolfowitz two years ago. He might be reluctant to turn his back on a promising private-sector career after less than a year. Carlos Gutierrez, 53, US Commerce Secretary. Form Having learned to speak English from a hotel porter in Miami and beginning his working life delivering breakfast cereals, this Cuban-born son of a pineapple plantation owner is undoubtedly the most colourful of the leading candidates. Mr Bush calls him 'a great American success story' for the way he rose through the ranks at Kellogg's from delivery driver to chief executive. He was six when his family fled Fidel Castro's Cuba in 1960 and settled in the US. He was hand-picked by Mr Bush to become commerce secretary in 2004 and has an affable style that made him a popular member of the president's inner circle. Like Mr Zoellick and Mr Kimmitt, he has key experience of the intricacies of global finance - one of his chief duties at the Commerce Department was to strengthen America's economy through the opening of worldwide markets and the expansion of free trade. 'He understands the world of business from the first rung of the ladder to the very top,' Mr Bush says of a man who was responsible for a US$6.5 billion budget at Commerce, more than two-thirds the amount the World Bank loaned to developing countries last year. Prospects Mr Bush might prefer to keep him in government but his Latin American roots would make him a popular choice among some developing countries. Other contenders Stanley Fischer, 63, governor of Bank of Israel. Form Born in what was then Rhodesia, he grew up among Africans and admits to being 'gripped' by problems of third-world development and debt crisis. Being the World Bank's chief economist from 1988 to 1990, he understands its complexities. He also has a deep knowledge of global finance, having been deputy managing director of the International Monetary Fund from 1994 to 2001. Prospects Noted as a unifier rather than a divider, but seen by some Republicans as too liberal. Paul Volcker, 79, economist Form As chairman of the Federal Reserve from 1979 to 1987, he lowered inflation but triggered a recession. Trouble-shooter, tough on financial corruption; exposed UN bribe-taking in Iraq's oil-for-food programme and chaired the panel investigating Holocaust-era Swiss bank accounts. Prospects A sound money man but age could hamper his chances. Bill Frist, 55, former Republican senator. Form Ex-Senate majority leader, heart surgeon, once tipped for US presidency. Pilot, director of World of Hope charity for Aids relief, has worked on medical projects in Africa. Shrewd investor, with stock holdings worth up to US$45m. Prospects Said by The Wall Street Journal to be receiving 'especially close scrutiny' from the White House, but federal investigation into claims of insider dealing could count against him, despite being cleared. Other names in the frame include Richard Levin, president of Yale University, and John Danforth, a former senator and US ambassador to the United Nations. The outsiders Tony Blair, 54, outgoing British Prime Minister. Form Described as 'a pain in the backside' by his school teachers but became political boy wonder and Labour Party's longest-serving prime minister, from 1997 to 2007. Helped broker peace in Northern Ireland but also co-sponsored unpopular war in Iraq, forcing downfall. Taxed the rich, championed the poor by raising minimum wage. Leaves a booming economy - GDP up, unemployment down, interest rates low. Prospects He may be Mr Bush's buddy but probably hails from the wrong side of the pond. 'I haven't talked to Tony Blair about it, but I do think it'd be good to have a US citizen run the bank,' Mr Bush has said. Another handicap: Blair admits he's shaky at maths. Paul Hewson, aka Bono, 47, singer and humanitarian activist. Form Politically charged, socially conscious Irishman with ability to talk the moneyed into parting with their cash. Avid campaigner against third-world debt, homelessness, poverty, global warming, disease and hunger. One-time friend of Pope John Paul II but also known to friends as the Antichrist for his fiery, combative tendencies. Three-time nominee for Nobel Peace Prize, twice named one of Time's 100 most influential people and an honorary knight. Once suggested tithing 1 per cent of the US national budget for world causes. Prospects Fits White House's criteria for World Bank chief to be 'someone with a passion for lifting people out of poverty' but is outspoken with dubious leadership style: 'Everyone argues, then we do what I say.'