The old Roman adage, “Divide and Conquer” is based on a certain technique that destroys the basic idea of truth. Agreement on facts between people is the ground floor of any cooperative action. Trust is required to accept facts as the best approximations of a truth that will be acted upon on. By destroying any trust in facts or truth there can be no agreement or cooperation possible between two entities. They are effectively divided and easily conquered by those who are not divided.
This is what will destroy American Democracy.
Ice on the Moon 