Mr. O’Sullivan is President and founder of the Danube Institute in Budapest, international editor of Quadrant Magazine in Sydney, Australia; associate editor of the Hungarian Review; a fellow of the National Review Institute and editor at large of National Review. He is a co-founder and director of Twenty-First Century Initiatives as well as the International Reagan Thatcher Society.
He served as a Special Adviser and speechwriter to Prime Minister Margaret Thatcher. He was the founder and co-chairman of the New Atlantic Initiative, launched at the Congress of Prague in May 1996 by President Vaclav Havel and Lady Thatcher. It played a major role in bringing the countries of Central and Eastern Europe into NATO.
His book, "The President, the Pope, and the Prime Minister," on the roles played by Pope John Paul II, President Reagan and Prime Minister Thatcher in the collapse of communism and the revival of Western market democracies, has been published in English, Portuguese, Spanish, Czech, Polish, Italian, and Hungarian.