Finno-Soviet Treaty of 1948

The Agreement of Friendship, Cooperation, and Mutual Assistance, also known as the YYA Treaty from the Finnish Ystävyys-, yhteistyö- ja avunantosopimus (YYA-sopimus) (Swedish: Vänskaps-, samarbets- och biståndsavtalet (VSB-avtalet)), was the basis for Finno–Soviet relations from 1948 to 1992. It was the main instrument in implementing the Finnish policy called Paasikivi–Kekkonen Line.

Under the treaty, which was signed on April 6, 1948, the Soviets sought to deter Western or Allied Powers from attacking the Soviet Union through Finnish territory, and the Finns sought to increase Finland's political independence from the Soviet Union. It thus ensured Finland's survival as a liberal democracy in close proximity to strategic Soviet regions, such as the Kola Peninsula and the old capital Leningrad.

Under the pact, Finland was obliged to resist armed attacks by "Germany or its allies" (in reality interpreted as the United States and allies) against Finland, or against the Soviet Union through Finland. If necessary, Finland was to ask for Soviet military aid to do so. However the pact in itself did not provide any provisions for the Soviet military to enter Finland and stipulated that all such actions would have to be agreed separately should Finland choose to request aid. Furthermore, the pact did not place any requirements for Finland to act should the Soviet Union be attacked (if the attack would not take place through Finland). The agreement also recognized Finland's desire to remain outside great-power conflicts, allowing the country to adopt a policy of neutrality in the Cold War.

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