During World War II he opposed the Nazis and Nazi Germany's takeover over Austria. Adolf Hitler ordered him to be put to death, but Habsburg left France and spent the war in the USA. Habsburg gave up his claim to the throne in 1961, and was allowed to return to Austria five years later. He was a member of the Christian Social Union of Bavaria and became a member of the European Parliament and pushed to get the former communist countries of Eastern Europe allowed into the European Union.