https://waitbutwhy.com/2023/02/wop-chapter-3.html
This is actually incredibly true. A lot of the increasing polarization we have seen since the 90s is due to external threats to the United States disappearing, and the United States falling into factions within itself. As the generations that remember the unity that kept Americans together to face the cold war threats die off, the new generations have only known us vs them internally not externally.