The man known as the "godfather of neoconservatism", Irving Kristol, has died from lung cancer aged 89.
Kristol rejected the communist beliefs of his youth to become a leading right-wing thinker and writer.
His ideas had a huge influence on the Bush administration and in 2002 he was awarded the Presidential Medal of Freedom by President George W Bush.
The magazine edited by his son William Kristol, The Weekly Standard, paid tribute to his "wisdom" and "wit".