In the aftermath of the Latvian War of Independence, the LKP was banned in Latvia. Its leadership resided in exile in the USSR, while the organisation in Latvia operated clandestinely, either through underground cells, or via proxy organisations, such as "Red" leftist trades unions. In 1928 the party started operating more openly, and contested the 1928 Saeima elections through a proxy list known as the "Left Trade Unions". The list won five seats, but was banned in 1930. They reformed the following year to contest the next elections as the "Trade Union Workers and Peasants Group", winning six seats. However, in 1933 the Supreme Court ordered the dissolution of the party, and its MPs were arrested and charged with treason. In 1936, a youth organization parallel to the LKJS, Workers' Youth League of Latvia, was formed as a cooperative effort by the LKP and their former rivals, the erstwhile Menshevik Latvian Social DemocraticWorkers' Party, outlawed following the Ulmaniscoup d'état in 1934.
After the Soviet occupation of Latvia in June 1940 and the ousting of the Ulmanis government, the LKP and LDJS were legalised again and could operate openly. It was the only party allowed to contest the Soviet staged 1940 elections, which it did under the name "Working People's Bloc". The party later merged into the Communist Party of the Soviet Union. As the Latvian branch of CPSU it was renamed as Communist Party of Latvia partija,. When the CPSU was renamed the Communist Party of the Soviet Union in 1952, the Latvian branch was reconstituted under the old name LKP. Article 6 of the Latvian SSR Constitution made the LKP's monopoly on political power in Soviet Latvia explicit. In 1990, the Supreme Council of the Republic of Latvia voted to remove Article 6 from the Constitution. On 14 April 1990, a pro-independence faction under Ivars Ķezbers split off from the LKP to form the Independent Communist Party of Latvia. The main body of the LKP, under the chairmanship of Alfrēds Rubiks, remained loyal to Moscow and the CPSU leadership. Later that same year, on 14 September, Ķezbers's party was officially renamed the Democratic Labour Party of Latvia and adopted nominally social-democratic platform.
Post-independence, 1990–1993
Following Latvia's renewed independence from the Soviet Union, the LKP was banned by a decision of the Supreme Council of the Republic of Latvia on 10 September 1991 as an organisation deemed hostile to Latvia's independence. In October of that year, the official newspaper of the Communist Party of Latvia Cīņa, was shut down and banned. Later, an organization by the name of the League of Communists of Latvia was created by Albert Lebedev. However, registration to this organization was denied. In 1993, it was indicated that the League of Communists of Latvia became affiliated to the Union of Communist Parties – Communist Party of the Soviet Union. Since then the party has operated underground and under "certain conditions" In 1994, the Socialist Party of Latvia was founded as the successor to the LKP.
Press
Cīņa was a newspaper founded in March 1904 as the Central Organ of the Latvian Social-Democrats. It was published periodically in Riga, Brussels and Petrograd. From 1919 it was the organ of the Communist Party of Latvia. While the LKP leadership was in exile in the USSR during the interwar years and the Nazi occupation in World War II, Cīņa was published in the Russian SFSR. From 1940 onwards it was published in Riga. In the Latvian SSR, Cīņa was one of the main Latvian-language dailies. In 1990, when the Ķezbers faction split from the main LKP to form the Independent Communists, they changed the name of the newspaper to Neatkarīgā Cīņa, which after privatisation in the 1990s later became Neatkarīgā Rīta Avīze. The Russian-language sister publication to Cīņa published by the LKP was the daily Sovetskaya Latviya ; while the daily Padomju Jaunatne was the newspaper of the Latvian Young Communist League. In the Latvian SSR, the LKP also published a monthly political journal Padomju Latvijas Komunists, with a parallel edition in Russian. The journal ceased publication in 1990.
First Secretaries of the Communist Party of Latvia
Second Secretaries of the Communist Party of Latvia