I think the Nation has been united in recent times. In the late 80s through the 2000s we were united as a nation. We had political differences, but that is healthy. Even in 2008 we had optimism that carried us out of a potential catastrophe. The fracture came in 2010 and broke wide open in 2012 with the Tea Party/Freedom Caucus. These monkeys came in with the agenda to prevent government from operating, and have been employing it since.
It's a concept that played with non-intellectuals and nonconformists, and remains so. To this date, the U.S. Senate has not passed meaningful legislature under Republican rule. Over 400 bills passed by the House has languished, untouched, the business of America not being considered due to the Republican's ridiculous reticence.