Quisling, Vidkun (1887-1945), Norwegian politician, whose collaboration with the Nazis...during World War II (1939-1945) made his name synonymous with traitor. In the 1930s he found the Nationa Union, a Fascist party that received subsidies from Germany. After the Nazi invasion of Norway in 1940 the National Union was declared the only legal party. The Germans installed Quisling as prime minister in 1942 and throughout the war he collaborated with the Nazis. Quisling was tried and executed after the war.

Other countries have had similar people: Benedict Arnold, Claus von Stauffenberg, William Joyce, Ferdinand Walsin Esterhazy, the Philby-Maclean-Burgess-Blunt-Cairncross group -- traitors or patriots? Or is "traitor" defined by which side wins?