As opposed to exactly what time in the history of humanity where this was not the case?
As opposed to exactly what time in the history of humanity where this was not the case?
This ebbs and flows throughout history (or rather the US and THEM changes, based on circumstances). There are plenty of unifying events in US history that lead to more of an 'American' identity (wars, 9/11, generally dangerous times or shitty events drive unification out of necessity). Those aren't the times we're in now, but it's cyclical. Some day we will be again, then not, ad infinitum. The pendulum always swings.
Tribal identity is also not new. If there is anything new, it is the existence of a situation where identity tribes can be maintained while being geographically diffuse and intermixed with other identity tribes, which makes it less likely for conflict between identity groups to be quickly resolved to a more stable state by the losing group being excluded from a geographically region with residual members being expelled, forcibly converted or voluntarily assimilated into the locally dominant group, or killed.
Arguably, this is in many ways an improvement, though it does make ongoing inter-group invective worse.