Superstitions have never sat very well with me, though I respect others'.
Before the Earth was destroyed, there was the United States. From what I understand, you're from that time and place. Think of the clans as the states themselves. Each of them have a territory, their own set of rules, and autonomy from the others, but then they're all underneath one larger government. An attack against one is an attack against all. They have larger protection. Crossing borders is easier, because you're part of the same Coalition.