Abraham was told to leave his home for a LAND that God would show him, and make of him a great NATION. For land and nation was why Abraham chose to follow the voice in his head. Without the land and the nationhood, "Judaism" has no earthly purpose and those who do not believe in Zionism might as well intermarry and leave the tribe. And thereby forfeit their right to the land.
Netanyahu: Most of Americans see eye to eye with Israel on dangers of Iran deal (Haaretz)
from the article: Lieberman: American Jews are facing demographic catastrophe