In a European context, the term Border states policy, and Border states in a specific sense, refer to attempts during the interbellum to unite the countries that had won their independence from Imperial Russia due to the Russian Revolution, the treaty of Brest-Litovsk, and ultimately the defeat of Imperial Germany in World War I. The policy aimed at a united defense against the threat of Communist expansionism and World Revolution.

The Border states policy was never particularly successful. Disputes and different allegiances within the group of border states hindered unity.

The following countries were, in this context, considered border states:

• Finland
• Estonia
• Latvia
• Lithuania
• Poland
• Belarus & Ukraine (until annexed by the Soviet Union)
• Czechoslovakia
• Romania

The Border states were commonly perceived as a cordon sanitaire, or buffer states, between the Soviet Union and the anti-Socialist powers in the West until the Molotov-Ribbentrop Pact (1939) in effect assigned their territory to either Nazi Germany or the Soviet Union.

With the exception of Finland, all Border states fell under Soviet occupation as a result of World War II.

See also

• Mitteleuropa