History of Lithuania
On February 16, 1918, Lithuania was re-established as a democratic state. It remained independent until the outset of World War II, when it was occupied by the Soviet Union under the terms of the Molotov–Ribbentrop Pact. Following a brief occupation by Nazi Germany after the Nazis waged war on the Soviet Union, Lithuania was again absorbed into the Soviet Union for nearly 50 years. In 1990–1991, Lithuania restored its sovereignty with the Act of the Re-Establishment of the State of Lithuania. Lithuania joined the NATO alliance in 2004 and the European Union as part of its enlargement in 2004.
Lithuanian Soviet Socialist Republic
Lithuania declared sovereignty on its territory on 18 May 1989 and declared independence from the Soviet Union on 11 March 1990 as the Republic of Lithuania. Lithuania was the first Baltic state to assert state continuity and the first Soviet Republic to remove "Soviet" from its name (though not the first Soviet Republic to assert its national sovereignty and the supremacy of its national laws over the laws of the Soviet Union; see Estonian Sovereignty Declaration). All legal ties of the Soviet Union's sovereignty over the republic were cut as Lithuania declared the restitution of its independence. The Soviet Union claimed that this declaration was illegal, as Lithuania had to follow the process of secession mandated in the Soviet Constitution if it wanted to leave.