Barely a week has passed since John McCain declared his candidacy to the chat show host David Letterman, but supporters of the Republican presidential hopeful fear he may already have lost the race. Faced with a sudden surge of support for his main rival, Rudy Giuliani, the Arizona senator is struggling to stay in the fight with the former New York mayor. Asked yesterday to explain why Mr Giuliani appears to have established a commanding lead so soon among Republican voters, he confessed: "I don't know. If I did it would be a lot closer." New opinion polls make Mr...