The informal term "Soviet Empire" is used by critics of the Soviet Union and Russian nationalists to refer to that country's perceived imperialist foreign policy during the Cold War. The nations said to be part of the "Soviet Empire" were officially independent countries with separate governments that set their own policies (to a greater or lesser extent, depending on the country), but those policies had to remain within certain limits decided by the Soviet Union and enforced by threat of intervention by the Warsaw Pact (Hungary 1956, Czechoslovakia 1968, Poland 1980). Countries in this situation are often called satellite states.