Marco Rubio came out on the winning end of a testy exchange with his longtime friend Jeb Bush and had an overall solid performance, according to many analysts, after the third Republican presidential debate of the primary season Wednesday.

Rubio, the fresh-face Florida senator, and Bush, the former governor of the same state, were among 10 presidential hopefuls that sparred, mostly over economic policy, at the debate in Boulder, Colorado.

Bush, who was once seen as a favorite of the Republican establishment but whose campaign has struggled to gain traction, attacked Rubio early in the debate for missing what he said were too many votes in the Senate.

“Marco, when you signed up for this, this was a six-year term,” said Bush. “And you should be showing up to work. I mean, literally, the Senate, what is it, like a French work week, where you get like three days where you have to show up?”

Rubio shot back quickly, accusing Bush of attacking him out of political expediency: “Someone has convinced you that attacking me is going to help you,” Rubio said to the man who in the past served as his mentor.

Trump on defensive

The debate, broadcast on financial cable news channel CNBC, comes as real estate mogul Donald Trump appears to be losing his months-long grip on the race’s frontrunner position.

Trump, the outspoken reality television star who now trails retired neurosurgeon Ben Carson in several national polls, appeared more subdued and on the defensive, compared to previous debates.

Early on, Trump reacted angrily when a moderator asked whether his tax plans, which some say would cause deficits, and his proposal to build a border wall to keep out Mexican immigrants meant he was running a “comic book” presidential campaign.

“That’s not a very nicely asked question the way you said that,” said Trump. He went on to defend his tax proposal, saying it would ensure the U.S. economy “would take off like a rocket ship.”

Carson defends tax plan

Carson, the soft-spoken political outsider, also fielded several attacks from rivals, including on his own tax plan, which he has said is inspired by the biblical concept of tithing.

“I didn’t say the rate would be 10 percent. I used a tithing analogy…. the rate would be much closer to 15 percent,” said Carson, an evangelical Christian. “You also have to get rid of all the deductions and loopholes.”

Ohio Governor John Kasich used the opportunity to pounce on both frontrunners. He slammed Carson’s and Trump’s tax proposals as “fantasy” and saying they were evidence the candidates are unqualified to become president.

“Folks, we’ve got to wake up,” said Kasich. “We cannot elect somebody that doesn’t know how to do the job. You have got to pick somebody who has experience, somebody that has the know-how, the discipline.”

Also at the debate were ex-Hewlett Packard executive Carly Fiorina, New Jersey Governor Chris Christie, ex-Arkansas governor Mike Huckabee, Texas Senator Ted Cruz and Kentucky Senator Rand Paul.

Crowded stage

The crowded stage made it more difficult to project a clear winner or loser, and also prevented in-depth discussion on issues, according to Northeastern University journalism professor Alan Schroeder.

“I thought it was sort of a big, sprawling debate, almost a little too sprawling. One of the things that happens with primary debates over the course of a cycle is that each time you watch there are one or two people gone from the previous time.”

“I think the fact that we keep having these enormous debates with this huge casts of characters – it makes it very difficult to focus on anything,” Schroeder told VOA.

Rubio solid

But Schroeder, the author of a book on U.S. presidential debate history, says Rubio was among those who shone brightest, particularly noting the back-and-forth with Bush.

“Rubio has an ability to really deflect incoming attacks on him, and Jeb Bush just seems to be really ham-handed when it comes to going after people,” Schroeder said.

Richard Temple, a California-based Republican strategist, agrees, saying Rubio could see a jump in the polls following the debate.

“Rubio’s been strong in every debate, but he’s now gaining traction as a more pragmatic Republican choice for those who decide they don’t want to vote for Donald Trump or Ben Carson,” Temple told VOA.

Trump stumbles

It was not the best night for Trump, who repeated some of the same talking points – almost verbatim – as in past debates. His performance, combined with his lagging poll numbers, suggest his downfall may have begun, according to Temple.

“Many people were thinking that Donald Trump wasn’t going to follow the rules of gravity,” said Temple. “I think that is starting now. He doesn’t have a depth that some of the other candidates who have held office.”

“His basically ‘one-note-Johnny’ message ultimately will start to weigh him down. I think he’s starting a slow erosion of his support, and voters will find somewhere else to go to.”

Attacks on media

Another potential loser in the debate was the media – specifically the CNBC moderators, who tried and failed several times to get the candidates to attack each other personally.

“I think everyone saw attacking the press to be a smart strategy. I’m not sure if it is, I think it’s kind of gratuitous. But it got the most applause,” said Republican pundit John Feehery.

Undercard debate

The main event followed an earlier “undercard” debate during which the lower-ranking candidates battled for attention.

Longtime Senator Lindsey Graham used the stage to attack Trump and his “Make America Great Again” slogan. “America is great,” he said. “I intend to make America strong again.”

Also participating in the warm-up debate were former senator Rick Santorum, Louisiana Governor Bobby Jindal, and former New York governor George Pataki, all of whom have barely registered any support in national polls.

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