The answer is racism. It is racism because they treated the Europeans from the north more better than Europeans from the south for no reason when they were essentially the same
They feared communism would spread.
The ancient Roman republic had three branches of government. In the beginning, the legislative branch was the Senate, a group made up of 300 citizens from Rome's patrician class, the oldest and wealthiest families of Rome. It was the patricians, tired of obeying the king, who revolted and threw out Tarquinius Superbus.
After the Soviets successfully detonated an atomic bomb in 1949, President Harry S. Truman ordered the creation of a hydrogen bomb project. With the help of the Polish mathematician Stanislaw Ulam, Dr. Teller developed a model for the hydrogen bomb known as the Teller-Ulam design