An entirely monotheistic system of governing
There will be a time during which all the inhabitants of earth believe in monotheism and reject polytheism:
Imam Sadiq (PBUH), describing the inclusive and universal government of Imam Mahdi (PBUH), stated that:
“In the East and the West of the world, there will not be anyone who does not believe in the oneness of God and monotheism.”
Bihar al-Anwar, volume 52, p. 340