Following Sen. Hillary Clinton's statement that presidential nominating contests have historically lasted late into the calendar year, citing the June 1968 assassination of Robert F. Kennedy as one example, an observer said the comment probably dooms any chance that she would be picked for the number two position by frontrunner Sen. Barack Obama.

"This probably means the end of her campaign," said David Mark, senior editor of Politico.com, on The Early Show. "She was already treading on pretty thin ice. To raise the specter of a tragic event like an assassination, this probably ends any vice presidential hopes she had."

Clinton was quick to apologize for the statement, saying Friday, "I regret that if my referencing that moment of trauma for our entire nation - and in particular the Kennedy family - was in any way offensive. I certainly had no intention of that whatsoever."

However, Mark doesn’t believe the retraction will work.

"She trying to walk this back as furiously, as quickly as she possibly can," he said. "But yes, the damage is essentially done. There's no way of taking it back. It's right there in black and white, on videotape. And whatever she meant, it will be taken a certain way."

What does this mean for talk of the "dream ticket," which has been building in part as a means to allow a graceful and perhaps productive way to end the standoff between the two presidential hopefuls?

Mark believed the chances of an Obama-Clinton pairing were slim before her comments on Friday. "I don't think he particularly gains much from having her on the ticket," he said. "I don't think he particularly needs her. Yes, half the Democratic Party is with her, but most Democrats are not going to go over and vote for John McCain" if their candidate doesn't get the nomination.