Question

How can a large group of people with different backgrounds,beliefs,and interest come together to form a political union

Answer 1

Or religious beliefs

Answer 2

You could almost look at the modern major parties in the United States. The Republican and Democrat parties are both filled with people that have a diverse range of ethnicities and religious beliefs.

Humanity is united through our shared beliefs and interests. We may not all align on all issues but we are all human.