John O'Sullivan was a key figure in Margaret Thatcher’s circle during her tenure as Prime Minister (1979–1990). A British conservative journalist and political commentator, he served as a speechwriter and policy advisor to Thatcher in the 1980s. His work helped shape her political messaging, particularly her staunch anti-communist stance and free-market policies. O'Sullivan’s intellectual contributions aligned with Thatcher’s vision of deregulation, privatization, and challenging Soviet influence, which were hallmarks of her leadership. He later wrote about Thatcher’s impact in his book, The President, the Pope, and the Prime Minister (2006), where he argued that Thatcher, alongside Ronald Reagan and Pope John Paul II, played a critical role in the collapse of the Soviet Union through their combined moral and political efforts. His close association with Thatcher also informed his broader career, including his editorship of National Review (1988–1997) and his current role as president of the Danube Institute in Budapest (since 2017).