Nothing Wrong with the Analogy
I'm getting a little tired of defending Hillary Clinton on this site, but I would just like to say that the recent spat of accusations in the blogosphere and pundit media that she's dropping hints that someone shouls assasinate Obama are off the charts. A typical bit of commentary comes from zFacts (no persistent link available at the time of writing).
She claims her statement meant that races often last till June. But why bring up a 40-year-old assassination to make this point? She claims it's because "We all remember" when Bobby was assassinated.
Did you remember it was in June? I sure didn't. She knows that almost no one remembers.
Actually, the point isn't that it was in June, but that Bobby Kennedy was the popular choice "nominee presumptive" at the analogous point in the cycle in 1968. It's true that the dates of the contest were all different then (and for that reason I doubt she expects anyone to remember the June date specifically) and that primaries mattered less than they do now - but the aggregate facts actually make it a good analogy. Whether or not you remember that Kennedy was killed in June specifically, some things that anyone familiar with the history will remember are that Kennedy was an initial long-shot who turned out to be a lot more popular than anyone expected. The DNC was deadset on nominating Humphrey (which they did without running him in a single primary, actually) after LBJ imploded in New Hampshire, and was sort of suprised when the challenge came from McCarthy. McCarthy's grassroots popularity inspired Kennedy to run, and he quickly became the more popular anti-war alternative, the voice of the left wing of the party. Gee, see any similarities that might be relevant? A candidate who is surprisingly popular, giving the presumptive winner at the outset a run for her money, and this largely on the basis that he is the more credible anti-war candidate, having actually voted against the Iraq War Resolution? I'm gonna go out on a limb and say that it's OK if anyone sees a parallel between Obama and Kennedy here.
To top that, there were two true examples from more recent years. Gary Hart and Ted Kennedy fought until the convention. The only reason to reach back 40 years to the assassination for a false example is to bring up Obama's vulnerability.
Let's start with Ted Kennedy. This would be the 1980 election, and Kennedy, unlike Clinton, campaigned well beyond the point where he could feasibly win. Remember that neither candidate this cycle has yet reached the threshold for nomination. That was not true in 1980. Though initially favored to beat Carter 2-to-1, the bottom had alreday mostly fallen out of Kennedy's campaign by November 1979. He flubbed a bunch of questions on a nationally televised interview, and the Iran Hostage Crisis did wonders for Carter's approval rating. Carter went into the convention with a 30% lead in pledged delegates (no superdelegates in 1980) over Kennedy, more than enough to force a victory. Kennedy had lost by March, in fact, and took the fight to the convention mostly out of spite, refusing to endorse Carter or even shake his hand on stage. Let's see a show of hands of anyone who can think of a reason why Clinton might not want to compare herself to Kennedy in 1980? Yup, that's everyone in the class.
What of Gary Hart? Well, this is admittedly a pretty good analogy in real terms, since Hart, like Clinton to Obama now, had mostly lost to Walter Mondale by June of 1984. He stayed on through June arguing that "Super Tuesday III" (there were a lot of contests in June that year) would vindicate him. His position was such that he couldn't really win the pledged delegate count, but the argument was that the superdelegates (yes, they were back in 1984) would see a strong showing for him on Tuesday III as a change in the wind and support him anyway at the convention. But the catch here, of course, is that Obama is Mondale and Clinton is Hart. She hardly makes her case by comparing herself to the eventual loser!
Now, the Clintons are not exactly paragons of straight-shooter politics, so on personality alone there's good reason to think she's dropping indecent hints. But let's stop all this talk about the Bobby Kennedy analogy being inappropriate. It's perfectly appropriate for what she was trying to say. In fact, I can't really think of a better one in living memory.