Politics may be history, but a lot of it is also mythology, and the problem comes when you believe the myth without understanding the history.
Undoubtedly you've noticed the comparisons during this campaign between Obama and Robert F. Kennedy, the idea that Obama is the next Bobby. That puts liberals of a certain age (you know, the ones with grey hair and ponytails who still worship the 60s) into a contemplative moode, and pretty soon they're musing themselves about how things would have been different if Bobby hadn't been assassinated - the war in Vietnam (Bobby would have brought the troops home), race relations (Bobby was a uniter), Watergate (Bobby would have kept that Nixon from being elected). The assassination of RFK was kind of the political equivalent of the day the music died - at least, whatever music remained after the death of JFK. (Which, as we detailed here, was a far more significant cultural event.)
Yes, Robert F. Kennedy does make for quite a mythic figure. Trouble is, as is so often the case with myth, the facts don't quite bear it out. It's popular to think that Sirhan Sirhan's bullets prevented Kennedy's election - but, in fact, it was doubtful that RFK would have even won the Democratic nomination.
For evidence, check out this collection of clips from network coverage of the California primary. As you can see, the consensus in this contemporaneous coverage - all coming prior to Sirhan's fatal shots - was that Hubert Humphrey (the eventual winner) was still the front-runner, even with Kennedy's triumph in California, and that it was highly unlikely that Kennedy would be able to deny Humphrey the nomination.
Of course, we really don't know what would have happened in 1968, and it's unlikely we'll ever be able to figure it out. The political world of 1968 bears no resemblance to that of today - what with favorite sons, surrogate candidates, party bosses and the prospect of multiple ballots at the convention - and it's doubtful that we can even comprehend how things operated back then.
Which is why it's so important to go back to the original source. Never mind what the historians say, or the movie makers, or the conspiracy buffs, or anyone else. Go back and find out what they were saying at the time. Bobby's assassination was a tragic event, and there's no doubt it impacted history - but not quite the way people think.
Many of Obama's more avid supporters like to see him as a reincarnation of Bobby Kennedy. But Bobby Kennedy, had he lived, probably wouldn't have won the nomination, let alone the election. Is that really what Obama's people want to emulate?