I specifically recall Kennedy and his main opponent in the primaries, Eugene McCarthy, appearing on Meet the Press together and discussing US support for Israel. Kennedy's support was unqualified while McCarthy sounded like an Arabist from the State Department.
A week later RFK was dead at the hands of a Palestinian.
If we are going to use 1968 as a starting point, the assassination of Robert Kennedy, who at the time was the probable democrat candidate and perhaps likely winner of the November election, at the hands of Palestinian Sirhan Sirhan should top this list.
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Freeper Diogenesis often posts his own list - starting with the assassination of Robert Kennedy.