Pat Buchanan's assertion that 1968 was one of the most divisive in American history is correct because:
There was a clash of opinions that made things dangerous in this year. One such opinion clash was between those who supported the Vietnam War and U.S. involvement in it, and those who didn't.
There were also high profile assassinations of leaders such as Robert Kennedy, and the support and opposition to the Civil Rights movement.
Find out more on the assassination of Robert Kennedy at https://brainly.com/question/11095889.