Boris Johnson, British Foreign Secretary, Drops Dual U.S. Citizenshipbr 8, 2017br LONDON — Boris Johnson, Britain’s colorful and blustery foreign secretary, who is perhaps best known for his leading role in campaigning for hisbr country’s departure from the European Union, has given up his American citizenship, a United States Treasury Department list showed Wednesday.br After Mr. Trump’s election, Mr. Johnson swiftly changed course, suggesting in Novemberbr that "there’s a lot to be positive about." He added, "It’s very important not to prejudge the president-elect or his administration." As mayor of London, Mr. Johnson cultivated the image of an endearing bumbler and came across like a comedian.br In an interview with National Public Radio in 2014, he described the "doctrine of global taxation" applied by the United States as "incredible." With a disheveled shock of blond hair, sharp witbr and clipped accent, Mr. Johnson sometimes seems like a caricature of the private-school-educated Briton.br As The Wall Street Journal reported, he is listed as Alexander Boris Johnson, abr shortened version of his full birth name, Alexander Boris de Pfeffel Johnson.br According to British news reports, as recently as 2015, he settled a hefty capital gainsbr tax bill on the sale of his north London home — after claiming that he wouldn’t pay.br His relations with Donald J. Trump took a blow in December 2015, when he accused Mr. Trump, then a presidential candidate, of being "out of his mind"br and of "a quite stupefying ignorance" that made him unfit for the presidency.br Born in New York, Mr. Johnson, 52, held dual citizenship until last year.