Einstein primarily emigrated to the United States because he had a Jewish background, and Adolf Hitler, who became Germany's chancellor in 1932, was about to adopt Anti-Semitic policies.
It was a very hard choice for Einstein to choose to emigrate to the United States, but it was a very wise one. As a Jew, he knew what was gonna happen if he stayed in the United States. You may already know that the Holocaust happened a few years later, in which most Jews living in countries occupied by Germany were murdered. Thanks to moving to the U.S, Einstein was safe from this event.
Answer:
Montesquieu called the idea of dividing government power into three branches the "separation of powers." He thought it most important to create separate branches of government with equal but different powers. That way, the government would avoid placing too much power with one individual or group of individuals.