I think that one specific way in which the events of 1968 impacted America was through a symbolic loss of hope. The assassinations of Bobby Kennedy and Dr. Martin Luther King, Jr. undermined feelings of hope. A nation besieged with the challenges of the Vietnam War and facing mounting crises on the domestic front surrounding issues of race and gender believed that leaders like Kennedy and King could shepherd it through a dark period. When both men were killed, many in the nation felt that hope was killed with them. In its place was a sinister unknown chartering the nation into an uncertain future.
The loss of hope was also displayed in the the Democratic Convention of 1968. Protesters chanted "The whole world is watching" while police officers abused them as they exercised their First Amendment rights. For a nation that was struggling with what to do and where to go, seeing its young people brutalized at the hands of police officers did not inspire hope. It was in this way that another tragic event of 1968 impacted the nation.