The legitimists of Austria and Hungary consider him the rightful king-emperor since his father's death. Before the Anschluss in Austria on the eve of the Second World War, the Workers' Party, known as Christian Syndicates, called unsuccessfully for Otto's return. 
In an interview given to a French newspaperwoman in 1950, Archduke Otto stated that Hitler offered him the opportunity to return to the Habsburg throne if he accepted and supported the Nazi ideology. He also stated that the Russians, in the late 1940s, intimated that an agreement with them was not out of the question. Otto refused both. 
In May 1951, Otto married Princess Regina of Saxe-Meiningen in Nancy, France. During the war Otto lived in Washington, DC, and since then he and his family have lived at various times in Luxembourg, England, and Germany. 
After the Second World War Archduke Otto returned to Austria but was later banished from the country by the Soviets, who were the occupying power. He and the family were permitted to re-enter Austria by order of the Austrian Supreme Court in 1966. 
Otto von Habsburg is extremely active in the world of political science---particularly as it relates to the European unification. His views of the world situation, and his dedication to the solution to 
the problems therein, are logical and appealing. He writes a regular newspaper column on world affairs, which is published simultaneously in Austria, Spain, Portugal, France, Belgium, Germany, Brazil, Peru, and in a number of papers in North America. He has travelled widely, and is in constant demand as a lecturer in universities and other academic circles in many countries. He has written twelve books on political science, world affairs, and history.
 

Source: Leo van de Pas