Republican Presidential Debate: 9 Moments That Mattered At The Second GOP Debate

— -- Former President Ronald Reagan’s 11th Commandment -- not criticizing a fellow Republican -- took more than a few hits Wednesday night, as the GOP presidential candidates sparred at the second debate of the primary season.

The showdown at the Ronald Reagan Presidential Library in Simi Valley, California, had significantly different stakes than the first debate. Establishment favorites Scott Walker and Jeb Bush flanked frontrunner Donald Trump last month, but they have been slipping in the polls.

Meanwhile, neurosurgeon Ben Carson is gaining momentum -- now the only candidate even close to Trump -- who has topped 30 percent in recent national polls and continues to lead in early states.

There was one additional podium this time: former Hewlett-Packard CEO Carly Fiorina was a last-minute add to the stage after gaining momentum in the polls because of a strong performance in the undercard debate last month.

Here is a look at the key moments at the second presidential debate:

1. Did Carly Win?

Carly Fiorina stole the show and possibly won the debate.

First, she took on Planned Parenthood and referenced undercover videos shot by the anti-abortion Center for Medical Progress which describe procedures in graphic detail.

“This is about the character of our nation, and if we will not stand up and force President Obama to veto this bill, shame on us,” Fiorina said, her voice raising and referring to the bill that is looking to defund Planned Parenthood.

Planned Parenthood has said the videos are “heavily edited” and has denied wrongdoing.

Shortly after the exchange, Tapper asked Fiorina about Trump’s comments to Rolling Stone magazine where he said, “Look at that face. Would anyone vote for that? Can you imagine that, the face of our next president?”

Fiorina’s retort, to huge cheers from the crowd: “You know, it's interesting to me, Mr. Trump said that he heard Mr. Bush very clearly and what Mr. Bush said [about women's health issues]. I think women all over this country heard very clearly what Mr. Trump said.”

Trump responded, “I think she's got a beautiful face and I think she's a beautiful woman.” Fiorina didn’t change her facial expression, but with a slight eye-roll she clearly won the exchange.

2. Donald Trump Insult-Fest

Donald Trump hurled the first insult out of nowhere: abruptly saying that Rand Paul didn’t belong on the stage. The slam came after saying he wouldn’t be “braggadocious” and after Fiorina pulled her punch in saying she wouldn’t question Trump’s ability to handle nuclear weapons.

Trump fired back after a Paul attack: “I never attacked him on his looks, and believe me, there’s plenty of subject matter.”

He then attacked Walker for problems in Wisconsin and for tanking in the polls –- and also said George Pataki is a “failed governor” who “wouldn’t be elected dogcatcher.”

He didn’t stop there, throwing out a snide side remark to Jeb Bush, standing next to him. “More energy tonight. I like that.” Trump has repeatedly hit the former Florida governor on his energy level, attacking him for having “low energy” on the campaign trail.

3. Jeb Bush Admits He Smoked Weed

His mom might not like it, but Bush says he smoked marijuana when he was young.

“So 40 years ago, I smoked marijuana,” he said. “I'm sure other people might have done it and may not want to say it in front of 25 million people. My mom’s not happy that I just did.”

He went on to call drugs in the United States “a serious problem.”