Betar is a historical Zionist movement and are actions are based on the clear philosophy of Zionist prophet Ze’ev Jabotinsky. Jabotinsky travelled Europe before the war and warned Jews to get out of Europe as a great fire was brewing, and if they stayed to defend themselves. As Jabotinsky said, “Liquidate the Diaspora before the Diaspora Liquidates You.”
Jabotinsky spoke on capitalism, human rights, and his Iron Wall security theme for the State of Israel continues to define Israel’s defense policy. His words are regarded as prophetic by many, and his followers have defined Jewish Zionist life.
These books are required reading to understand the basis of the Betar movement.
The Deafening Silence/American Jewish Leaders and the Holocaust
https://www.amazon.com/Deafening-Silence-American-Leaders-Holocaust/dp/0933503636
The Deed
https://www.amazon.com/Deed-Gerold-Frank/dp/0425039137
Perfidy by Ben Hecht
Perfidy Kindle Edition