Karl Liebknecht in the context of "Trotskyists"

The proclamation of the republic in Germany took place in Berlin twice on 9 November 1918, the first at the Reichstag building by Philipp Scheidemann of the Majority Social Democratic Party of Germany (MSPD) and the second a few hours later by Karl Liebknecht, the leader of the Marxist Spartacus League, at the Berlin Palace.

In the German Revolution of 1918–1919, during which Social Democrats and Spartacists were among the groups that fought to determine the country's future form of government, it was the MSPD and the ideas of the bourgeois-democratic parties that prevailed over the Spartacists and their more radical idea of a soviet-style republic. The German Empire was transformed from a monarchy into a parliamentary democratic republic with a liberal constitution. Scheidemann's speech marked the point at which the Empire could be said to have ended and the Weimar Republic born.

The Communist Party of Germany (German: Kommunistische Partei Deutschlands, pronounced [kɔmuˈnɪstɪʃə paʁˈtaɪ ˈdɔʏtʃlants] ; KPD [ˌkaːpeːˈdeː] ) was the major far-left political party in the Weimar Republic during the interwar period, an underground resistance movement in Nazi Germany, and a minor party in Allied-occupied Germany and West Germany during the post-war period until it merged with the SPD in the Soviet occupation zone in 1946 and was banned by the West German Federal Constitutional Court in 1956.

The construction of the KPD began in the aftermath of the First World War by Rosa Luxemburg's and Karl Liebknecht's faction of the Independent Social Democratic Party of Germany (USPD) who had opposed the war and the Majority Social Democratic Party of Germany (MSPD)'s support of it.

Trotskyism (Russian: Троцкизм, Trotskizm) is the political ideology and branch of Marxism and Leninism developed by Russian revolutionary and intellectual Leon Trotsky along with some other members of the Left Opposition and the Fourth International. Trotsky described himself as an orthodox Marxist, a revolutionary Marxist, and a Bolshevik–Leninist as well as a follower of Karl Marx, Friedrich Engels, Vladimir Lenin, Karl Liebknecht, and Rosa Luxemburg. His relations with Lenin have been a source of intense historical debate. However, on balance, scholarly opinion among a range of prominent historians and political scientists such as E. H. Carr, Isaac Deutscher, Moshe Lewin, Ronald Suny, Richard B. Day and W. Bruce Lincoln was that Lenin's desired "heir" would have been a collective responsibility in which Trotsky was placed in "an important role and within which Stalin would be dramatically demoted (if not removed)".

Trotsky advocated for a decentralized form of economic planning, workers' control of production, elected representation of Soviet socialist parties, mass soviet democratization,the tactic of a united front against far-right parties,cultural autonomy for artistic movements, voluntary collectivisation, a transitional program, and socialist internationalism. He supported founding a vanguard party of the proletariat, and a dictatorship of the proletariat (as opposed to the "dictatorship of the bourgeoisie", which Marxists argue is a major component of capitalism) based on working-class self-emancipation and council democracy. Trotsky also adhered to scientific socialism and viewed this as a conscious expression of historical processes. Trotskyists are critical of Stalinism as they oppose Stalin's theory of socialism in one country in favour of Trotsky's theory of permanent revolution. Trotskyists criticize the bureaucracy and anti-democratic current developed in the Soviet Union under Stalin.

The Spartacus League (German: Spartakusbund) was a left revolutionary movement organized in Germany during World War I and immediately thereafter. It was founded in August 1914 as the International Group by Rosa Luxemburg, Karl Liebknecht, Clara Zetkin, and other members of the Social Democratic Party of Germany (SPD) who were dissatisfied with the party's official policies in support of the war. In 1916 it renamed itself the Spartacus Group and in 1917 joined the Independent Social Democratic Party of Germany (USPD), which had split off from the SPD as its left wing faction.

During the November Revolution of 1918 that broke out across Germany at the end of the war, the Spartacus Group re-established itself as a nationwide, non-party organization called the "Spartacus League" with the goal of instituting a council republic that would include all of Germany. It became part of the Communist Party of Germany (KPD) when it was formed on 30 December 1918 and at that point ceased to exist as a separate entity.