Which countries were involved in the Polish-Soviet War?

The Polish-Soviet War, which took place between 1919 and 1921, primarily involved Poland and Soviet Russia. This conflict arose from the aftermath of World War I, as both nations sought to assert control over territories that had once been part of the old empires in Eastern Europe.

Poland had regained its independence after over a century of partitions, while Soviet Russia was attempting to expand its influence and promote communism. The war was characterized by significant battles, such as the Battle of Warsaw in 1920, which was crucial for Poland's defense against the Soviet advances.

The conclusion of the conflict resulted in the Treaty of Riga in 1921, which established borders that favored Poland and ensured its status as a sovereign state. This context solidifies why Poland and Soviet Russia were the key players in this war, making them the correct answer to the question. Other countries mentioned, such as Germany, France, or the United States, did not engage directly in the conflict, thereby eliminating them from consideration.