In 1940, in accordance with the secret protocol of the Molotov-Ribbentrop Pact with Nazi Germany, the Soviet Union directed the occupation and subsequent annexation of Estonia, Latvia, and Lithuania. In each country, demands were made under threat of force from Moscow for puppet communist governments to be formed. Fraudulent elections were held in July 1940 electing solely communists to be represented in the parliament of each country's government, and those governments then were instructed by Moscow to petition the Soviet government to be added as constituent republics of the USSR.
The United States, like other Western democratic powers such as the United Kingdom, Norway, France, and Denmark, never recognized this incorporation as valid and continued to accredit the legations of Estonia, Latvia, and Lithuania. On June 23, 1940, US Under Secretary of State Sumner Welles declared the US' non-recognition policy on the principles of the Stimson Doctrine. This policy was maintained until the restoration of independence in all three countries in 1991.
In 1953, the House of Representatives passed House Resolution 346 calling for a special investigation into the incorporation of the Baltic States into the USSR. The House Baltic Committee was then established to oversee the investigation which was chaired by Charles J. Kersten.
The investigations were held between November 30 and December 11, 1953, and a report was filed by the commission in February 1954. During the investigation, the House Baltic Committee interviewed approximately 100 witnesses including Johannes Klesment, a former Estonian government official, Jonas Cernius, the former prime minister of Lithuania, Juozas Brazaitis, the acting foreign minister of Lithuania, and former US President Herbert Hoover, all of whom provided testimony and additional information about Soviet activities in Estonia, Latvia, and Lithuania in 1940.
The significance of the Kersten Commission was primarily related to the US' non-recognition policy of the Soviet incorporation of Estonia, Latvia, and Lithuania. However, the investigation at the time was seen as a way for the US Congress to better study the manner in which the Soviet Union was able to direct the seizure of power in foreign countries. Specifically, the investigation coincided with US involvement in the Korean War and was seen by investigators as a way of studying communist methods that could be used in better articulating policy related to that conflict.
Baltic States Investigation, Hearings Before the Select Committee to Investigate the Incorporation of the Baltic States into the USSR, Eighty-Third Congress, First Session, Under Authority of H. Res. 346, Part I (1954)