Complex sentence: As Nazi persecution tightened its grip on the Jewish population, many who wished to leave Germany were prevented by the immigration laws of the Third Reich, forcing them to stay and suffer from the titanic wave of overt antisemitism sweeping the country.
Split into simpler sentences: As Nazi persecution tightened its grip on the Jewish population many who wished to leave Germany were prevented from doing so by the immigration laws of the Third Reich. As a result the Jews in Nazi Germany were forced to stay and suffer from the titanic wave of naked and overt antisemitism that was sweeping the country.