Leading up to the convention, it had been a difficult year for all of America. 1968 was characterized by tragedy and confrontation. On April 4th, the Civil Rights leader Martin Luther King Jr. has been assassinated.
Also in April, students at Columbia University had essentially shut down their institution in protest of several University policies.
Later, on June 5th, John F. Kennedy's brother, Bobby Kennedy, had been shot and killed.
Also, "on March 31, President Johnson announced he would not seek re-election. Johnson's favorability ratings were in the mid-30% range and polls showed even less support for his Vietnam War policies (about 23%.)"
The face of the nation was constantly changing. The movements that defined the year were losing their leaders and tensions continued to climb.