HRC was talking about pressure for her to drop out of the race before June and that historically candidates have stayed in the race until June. She was not talking about "something could happen to the Obama campaign and examples of this are...", she was talking about "people have stayed in the race until June before and examples of this are..."
HRC: People have been trying to push me out of this ever since Iowa.
Q: Why?
HRC: I don't know. [snip]
Q: So you don't buy the party unity argument?
HRC: I don’t because again I've been around long enough.
My husband did not wrap up the nomination in 1992 until he won the California primary somewhere in the middle of June, right?
We all remember Bobby Kennedy was assassinated in June in California. I don’t understand it. There's lots of speculation about why it is.
Q: What is your speculation?
I don't know. I find it curious. And I don't want to attribute motives or strategies to people because I don't really know, but it's a historical curiosity to me.
Clearly, the context here is discussing previous examples of races that had continued into June. I had watched the entire video at Argus Leader, and she had previously been mentioning examples of candidates that had taken it to the convention in 1980, 1984 and 1988.
Clearly, there was no need to bring up 1968.
But it seems like she was only trying to suggest that both her husband's 1992 campaign and the 1968 campaigns continued into June, and she was mentioning the assassination because it was a memorable event that most people could recall. "We all remember"...
So it was a poorly worded statement, and a horrible gaffe, and in extremely ill taste. She should issue a statement of apology. However, I don't think she quite meant to suggest that the possibility of Obama being assasinated was a justification for her staying in the race. That'd be an incredibly dumb thing to deliberately suggest, for any reason. She sticks her foot in her mouth, but I don't think she's deliberately suicidal.