After world war ii stalin said that the soviet union needed a buffer zone to protect it from attacks this idea resulted in the ussr expanding its control into

 EASTERN EUROPE

Context/explanation:

US president Franklin Roosevelt, British prime minister Winston Churchill, and Soviet premier Joseph Stalin, the leaders of the Allies in World War II, met at Yalta in February, 1945.  

Churchill and Roosevelt pushed strongly for Stalin to allow free elections to take place in the nations of Europe after the war. At that time Stalin agreed, but there was a strong feeling by the other leaders that he might renege on that promise. The Soviets never did allow those free elections to occur. Later, Winston Churchill wrote, ""Our hopeful assumptions were soon to be falsified." Stalin and the Soviets felt they needed the Eastern European nations as satellites to protect their own interests.   A line of countries in Eastern Europe came into line with the USSR and communism.  Churchill later would say an "iron curtain" had fallen between Western and Eastern Europe.

one of the main reasons was definitely slavery. back in 1861, republican abraham lincoln was elected and ended up being a major influence in the slavery business. slavery greatly affected the texas economy because back in 1845 during the annexation of texas, slaves became a big part of the texas population. many texans that were in favor of the secession influenced groups through party ties.