Ernst Leonhardt (September 25, 1885 – March 26, 1945) was an American-born Swiss military figure and pro-Nazi politician.

Ernst Leonhardt was born to a German-born Swiss father on September 25, 1885, in Tracy City, Grundy County, Tennessee, United States.^[1] Leonhardt moved to Switzerland at an early age to attend school at Basel, before joining the Swiss Army, where he rose to the rank of major.^[2]

Leonhardt became involved in politics in 1932 when he joined the National Front, and before long he had risen to the rank of Gauführer (equivalent to Gauleiter) in both Basel-City and the Canton of Solothurn.^[2] However he clashed with his superiors and in 1933 he left the Front and set up his own Volksbund with fellow dissident Emil Sonderegger.^[2] The group was dominated by the forceful personality of Leonhardt, a strong factor in its failure to attract much of a following.^[2] He also founded the Schweizerische Gesellschaft der Freunde einer autoritären Demokratie [de] (SGAD) (Swiss Society of Friends of an Authoritarian Democracy) in 1938 (a group officially banned in 1940, although in existence until 1941^[2]), whilst he was also a member of Franz Burri's Nationalsozialistischer Schweizerbund [de] and Nationalsozialistische Bewegung in der Schweiz.^[2]

Although Leonhardt continued to be involved in Swiss pro-Nazi movements, he had in fact relocated to Germany in 1939 and continued his activism from there.^[2] He worked closely with Burri to distribute Nazi propaganda into Switzerland, whilst also recruiting volunteers for the SS and arguing for an Anschluss-style takeover of Switzerland by Hitler. Leonhardt's Swiss citizenship was revoked in 1943 due to this idea.^[1][2] In his absence, the Swiss courts found Leonhardt guilty of attacking the Swiss Confederation's independence and illegally recruiting for a foreign military (i. e. the SS), sentencing him to fifteen and a half years in prison.^[1] However, he remained free in Germany for the rest of his life, continuing to produce propaganda.^[2] He was killed in an air raid on March 26, 1945, in Oberndorf am Neckar, Rottweil (district), Baden-Württemberg, Germany.^[1][2]

• Berne Trial

• Courtroom Battle of World War II (Part 1 of 3). contains information on the careers and fates of some of the Nazi collaborators.
• Courtroom Battles of World War II (Part 2 of 3).
• Courtroom Battles of World War II (Part 3 of 3).