From the link you provided....
World order can be founded only on an unshakeable consciousness of the oneness of mankind, a spiritual truth which all the human sciences confirm. Anthropology, physiology, psychology, recognize only one human species, albeit infinitely varied in the secondary aspects of life. Recognition of this truth requires abandonment of prejudice—prejudice of every kind—race, class, colour, creed, nation, sex, degree of material civilization, everything which enables people to consider themselves superior to others.
Acceptance of the oneness of mankind is the first fundamental prerequisite for reorganization and administration of the world as one country, the home of humankind. Universal acceptance of this spiritual principle is essential to any successful attempt to establish world peace. It should therefore be universally proclaimed, taught in schools, and constantly asserted in every nation as preparation for the organic change in the structure of society which it implies.
In the Bahá’í view, recognition of the oneness of mankind “calls for no less than the reconstruction and the demilitarization of the whole civilized world—a world organically unified in all the essential aspects of its life, its political machinery, its spiritual aspiration, its trade and finance, its script and language, and yet infinite in the diversity of the national characteristics of its federated units.”
And how that going to happen? In the U.S. there's just two main political parties and they hate each other.