The meaning of the word Freikorps changed over time. After 1918, the term was used for the paramilitary organizations that sprang up around Germany as soldiers returned in defeat from World War I. They were the key Weimar paramilitary groups active during that time. Many German veterans felt disconnected from civilian life, and joined a Free Corps in search of stability within a military structure. Others, angry at their sudden, apparently inexplicable defeat, joined up in an effort to put down communist uprisings or exact some form of revenge. They received considerable support from Minister of Defense Gustav Noske , a member of the Social Democratic Party of Germany, who used them to crush the German Revolution of 1918-1919 and the Marxist Spartacist League and arrest Karl Liebknecht and Rosa Luxemburg , who were killed on 15 January 1919. They were also used to defeat the Bavarian Soviet Republic in May 1919.
On 5 May 1919, members of Freikorps Lützow in Perlach near Munich, acted on a tip from a local cleric and arrested and killed twelve alleged communist workers (most of them actually members of the Social Democratic Party). A memorial on Pfanzeltplatz in Munich today commemorates the incident.
Freikorps also fought against the communists in the Baltic, Silesia, Poland and East Prussia after the end of World War I, including aviation combat, often with significant success. Anti-Slavic racism was sometimes present, although the ethnic cleansing ideology and anti-Semitism that would be expressed in later years had not developed. In Latvia, Freikorps murdered 300 civilians in Mitau who were suspected of having “Bolshevik sympathies”. After the capture of Riga, another 3000 alleged communists were killed, including summary executions of 50–60 prisoners daily. Though officially disbanded in 1920, many Freikorps
attempted, unsuccessfully, to overthrow the government in the Kapp Putsch in March 1920. Their attack was halted when German citizens loyal to the government went on strike, cutting off many services and making daily life so problematic that the coup was called off.
In 1920, Adolf Hitler had just begun his political career as the leader of the tiny and as-yet-unknown Deutsche Arbeiterpartei/DAP German Worker’s Party, which was soon renamed the Nationalsozialistische Deutsche Arbeiterpartei/NSDAP (National Socialist German Workers Party) or Nazi Party in Munich. Numerous future members and leaders of the Nazi Party had served in the Freikorps, including Ernst Röhm, future head of the Sturmabteilung, or SA, Heinrich Himmler, future head of the Schutzstaffel, or SS, and Rudolf Höss , the future Kommandant of the Auschwitz concentration camp. Hermann Ehrhardt , founder and leader of Marinebrigade Ehrhardt, and his deputy Commander Eberhard Kautter , leaders of the Viking League, refused to help Hitler and Erich Ludendorff in their Beer Hall Putsch and conspired against them.
Hitler eventually viewed some of them as threats. A huge ceremony was arranged on 9 November 1933 in which the Freikorps leaders symbolically presented their old battle flags to Hitler’s SA and SS. It was a sign of allegiance to their new authority, the Nazi state. When Hitler’s internal purge of the party, the Night of the Long Knives, came in 1934, a large number of Freikorps leaders were targeted for killing or arrest, including Ehrhardt and Röhm. Historian Robert GL Waite claims that in Hitler’s “Röhm Purge” speech to the Reichstag on 13 July 1934, he implied that the Freikorps were one of the groups of “pathological enemies of the state”.