BOULDER, Colorado — The biggest story from last night's debate wasn't Marco Rubio's strong performance (which it was), Ted Cruz stealing a moment (which he did), or the candidates and GOP audience attacking the media (which most definitely happened). Rather, the most significant story from last night is that Jeb Bush's campaign now finds itself on life support, especially after Bush swung and missed when trying to hit Rubio over his Senate voting record. As one Republican operative told NBC's Peter Alexander, Bush had to demonstrate to his supporters and donors -- after a rough last few weeks -- that the former Florida governor could land a punch, particularly after telegraphing to the political world that it was coming. But Bush missed. Badly. It was the equivalent of a teenager who, after telling the whole school that he was going to fight a classmate at lunchtime, ended up being the one taking the licking. We've covered politics long enough to know that a presidential candidate can rise from the dead (John McCain), withstand a bad debate performance (Barack Obama), and shine when it counts rather than months before the first votes are cast (John Kerry). But Jeb Bush is in trouble right now. Big trouble.
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Bush has to do something to buy time: For Bush, last night's debate will either be the moment that ended his presidential campaign, or the point when his campaign hit rock bottom (because he can't go any lower, right?). But to buy time, Team Bush has to do SOMETHING to calm the campaign's most ardent supporters -- whether it's new campaign staff or Bush admitting to strategic mistakes. The bad news for the campaign was last night. The silver lining: Every president and nominee has faced some near-death experience.
Last night's winners: Here are the GOP candidates who had a successful debate performances last night:
- Marco Rubio: He easily parried Jeb Bush's attack, he invoked his humble upbringing to defend his finances, he blasted the media, and he even whacked Hillary Clinton's Benghazi committee testimony. (But Rubio did display a potential general-election weakness: The conservative Tax Foundation DOES show that his tax plan benefits the wealthy more than the middle class -- see here.) This was Rubio's third-straight good debate performance. But he didn't really capitalize on his first two. Does that finally change?
- Ted Cruz: Last night was, by far, his best debate showing. And while he railed against the media instead of answering the question he was asked, that kind of rhetoric is music to the ears of conservative voters (even though John Kasich and Bush were the ones who gladly picked the fights Cruz was talking about). By the way, Cruz's attack on the media was almost word for word what a debate prepper told Politico's Playbook the morning before the debate: "I think you're going to hear a lot of, 'Well, we didn't see any of this tit-for-tat at that time in the Democrat debate.'"
- John Kasich: Unlike Bush, Kasich delivered in his telegraphed hit -- against Donald Trump and Ben Carson -- early in the debate, stealing a moment. But Kasich seemed to disappear after that. Question: Would that Kasich attack on Trump and Carson have been even more effective if it HADN'T been telegraphed?
- Chris Christie: Like in last month's debate, Christie had a nice performance, despite not being at the center of attention like some of the other candidates.
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Last night's losers: Here are the candidates who didn't have great debate performances:
- Jeb Bush: See above.
- Mike Huckabee: For someone who stood out time and time again in the 2008 campaign, Huckabee last night didn't steal a moment.
- Rand Paul: Ditto.
- Carly Fiorina: She certainly went out of her way to avoid being ignored, but her performance paled in comparison to last month's.
Last night's mixed performances: Trump and Carson:
- Donald Trump: His Lehman Brothers attack on Kasich was vintage Trump. But for someone who was the center of attention in the previous two debates, Trump no longer seemed like the big dog in the GOP race. And that's a potential problem for him going forward.
- Ben Carson: It will be interesting to see if Carson continues to rise in the polls, despite being the most reserved of the candidates at these debates. Like Cruz and Rubio, he attacked the media. But as this video demonstrates, Carson has MUCH closer ties to Mannatech than he admitted at last night's debate. See this piece by National Review: Ben Carson's Troubling Connection.
NBC News' Leigh Ann Caldwell contributed to this article, which first appeared on NBCNews.com.