Pre-Crisis Phase (August 8, 1920-December 15, 1926): Lithuanian and Bolshevik Russian representatives signed the Treaty of Moscow on July 12, 1920, which provided for Bolshevik Russian recognition of Lithuanian independence. Bolshevik Russian troops occupied Vilnius on July 15, 1920. The Lithuanian parliament ratified the Treaty of Moscow on August 8, 1920. Lithuanian troops took control of Vilnius on August 24-26, 1920. Lithuania signed a peace treaty with Poland on October 7, 1920, and Polish irregular troops commanded by General Zeligovski occupied Vilnius on October 9, 1920. Lithuania was admitted to the League of Nations (LON) on September 22, 1921. Denmark and Sweden provided diplomatic assistance (diplomatic recognition) to the government on September 29, 1921. The Norwegian government provided diplomatic assistance (diplomatic recognition) to the government on September 30, 1921, and the Dutch government provided diplomatic assistance (diplomatic recognition) to the government on October 7, 1921. Finland provided diplomatic assistance (diplomatic recognition) to the government on October 16, 1921. Ernestas Galvanauskas formed a government as prime minister on February 2, 1922. Poland formally annexed Vilnius on March 24, 1922. The Supreme Council of the Allied Powers (Britain, France Italy, and Japan) provided diplomatic assistance (diplomatic recognition) to the government of Prime Minister Galvanauskas on June 30, 1922. The U.S. government provided diplomatic assistance (diplomatic recognition) to the government of Prime Minister Galvanauskas on July 27, 1922. The Constituent Assembly adopted a constitution on August 1, 1922, and the constitution went into effect on August 6, 1922. Parliamentary elections were held on October 10-11, 1922, and the Christian Democratic Bloc (CDB) won 38 out of 78 seats in the parliament (Seimas). The Peasant Populist Union (PPU) won 20 seats in the Seimas. The Swedish government provided diplomatic assistance (diplomatic recognition) to the government on November 10, 1922. The Supreme Council of the Allied Powers (Britain, France, Italy, and Japan) provided diplomatic assistance (diplomatic recognition) to the government on December 20, 1922. Antanas Stulgenskis was elected president by the Seimas on December 21, 1922. Lithuanian troops occupied and annexed Klaipeda (Memel) on January 15, 1923. The parliament was dissolved in March 1923. Parliamentary elections were held on May 12-13, 1923, and the CDB won 40 out of 78 seats in the Seimas. The PPU won 16 seats in the Seimas. Parliamentary elections were held on May 8-10, 1926, and the CDB won 30 out of 81 seats in the Seimas. The PPU won 22 seats in the Seimas. Kazys Grinius of the PPU was elected president by the Seimas on June 7, 1926, and Mykolas Slezevicius formed a government as prime minister. Lithuanian and Soviet Russian representatives signed a non-aggression pact on September 28, 1926.
Crisis Phase (December 16, 1926-August 6, 1940): General K. Ladya and Colonel Povilas Plechavicius led a military rebellion against the government of Prime Minister Slezevicius on December 16-17, 1926. Augustinas Voldemaras of the Nationalist Union (NU) formed a government as prime minister on December 17, 1926. President Grinius resigned on December 18, 1926, and Antanas Smetona was elected president by the Seimas on December 19, 1926. President Smetona dissolved the Seimas on April 12, 1927. President Smetona proclaimed a new constitution on May 15, 1928, and the constitution establishing a strong presidency went into effect on May 25, 1928. Prime Minister Voldemaras resigned on September 19, 1929, and Juozas Tubelis formed a government on September 23, 1929. Former Prime Minister Voldemaras was tried for treason in May 1930. President Smetona was re-elected for a seven-year term on December 11, 1931. The government decided to dissolve opposition political parties on December 28, 1935, and opposition political parties were formally banned on February 6, 1936. Parliamentary elections were held on June 9-10, 1936, and the Seimas convened on September 1, 1936. A new constitution which limited the power of the parliament was adopted by the parliament on February 11, 1938, and the new constitution went into effect on May 12, 1938. President Smetona was re-elected on November 14, 1938. General Jonas Cernius formed a national coalition government as prime minister on March 28, 1939, but he resigned as prime minister on April 8, 1939. Lithuania declared its neutrality in World War II on September 2, 1939. The Soviet Union demanded access to Lithuanian territory for military purposes on June 14, 1940, and Soviet troops entered Lithuania on June 15, 1940. President Smetona protested the occupation and fled from Lithuania. The Communist Party of Lithuania (CPL) was legalized on June 25, 1940. Parliamentary elections were held on July 14-15, 1940, and the Union of Labor Lithuania (ULL) won 99 percent of the vote. The parliament voted in favor of Lithuanian incorporation into the Soviet Union on July 21, 1940, and the Soviet Union formally annexed Lithuania on August 6, 1940.
[Sources: Brecher and Wilkenfeld, 1997, 252-255, 571-573, 596-597; Gerutis 1969; Langer, 1972, 1040-1041; Rauch 1974; Survey of International Affairs (SIA), 1925 (supplement), 186-189, 1929, 509, 1935, 422, 1938, 705.]