The country responded to these traumas by in a sense, splitting up and falling apart. After 1968, the country was much more divided than it ever had been before. This split did not just happen out of nowhere. The country had been pulling apart because of things like Vietnam and the Watts riots.
But 1968 really accelerated the process. Things like the assassination of Martin Luther King and Nixon's "southern strategy" helped to polarize the country on racial lines. The Tet Offensive exacerbated the splits over Vietnam. Now, the country really started to fly apart, splitting into traditionalists who moved towards the Republican Party and people who wanted new ways and moved towards the Democratic Party. In a sense, we are still undergoing this movement.