By Daniel Malloy, ajc.com Staff Writer

Donald Trump will again be the focal point and ratings magnet for Wednesday night’s third Republican presidential debate.

But for the first time since rocketing to the top of the polls this summer, Trump is firmly on the defensive, with a rival eclipsing him in some recent surveys.

Ben Carson, the soft-spoken neurosurgeon and fellow political newcomer, has led Trump in recent polls in Iowa. And a CBS/New York Times poll out Tuesday showed Carson ahead of Trump nationally but within the margin of error, 26 percent to 22 percent.

“Trump’s entire mantra was that he’s ahead,” Newt Gingrich, the former House speaker and presidential candidate from Georgia, said Tuesday in Atlanta.

“Now he has his first bad national poll. And how he adjusts to the reality, and how he performs tomorrow night, is now the story.”

Wednesday’s debate among the top 10 polling Republicans starts at 8 p.m. at the University of Colorado at Boulder. An undercard debate featuring four candidates who trail in national polls starts at 6 p.m.

CNBC will televise the matchups, with its moderators’ questions to focus on pocketbook matters.

The first two Republican debates drew record-smashing ratings and helped shape the race. Trump courted controversy and steamrolled the competition in Cleveland in August. In California in September, the billionaire was silent for long stretches and took more criticism. Now that his polling dominance has slipped, Trump will be under even more scrutiny.

Trump has placed heightened importance on polls of all kinds, listing their results at the start of stump speeches as a way to declare his dominance. Now, he appears flummoxed.

“I don’t get it,” Trump said Tuesday on MSNBC’s “Morning Joe.” “I’m going there (to Iowa) actually today, and I have tremendous crowds and tremendous love in the room and, you know, we seem to have hit a chord. But some of these polls coming out, I don’t quite get it. “

In the surest sign of Carson’s rise, Trump has started attacking the neurosurgeon — without Carson launching the first strike. On Saturday, Trump mentioned Carson’s Seventh-day Adventist faith, which some evangelical Christians consider outside the mainstream, by saying “I don’t know about” it, as compared with his own “middle-of-the-road” Presbyterianism.

On Tuesday, Trump said, “Ben wants to knock out Medicare,” as an attack on Carson’s idea to replace the seniors’ health insurance program with savings accounts.

Carson has gone a more subtle route in undercutting Trump. Asked about Trump’s religion comment on “Fox News Sunday,” Carson replied: “Well, it’s kind of interesting because the conflict that we had a couple of months ago is he thought I was questioning his faith and he went ballistic on that. So it seems a little interesting that he would now be doing that.

“You know, I really refuse to really get into the mud pit,” Carson continued. “You know, Hillary (Clinton) actually was right when she said, you know, that the Republicans are there trying to destroy each other. I really think that was a huge mistake in the last cycle, and I’m certainly not going to get into that no matter what anybody says.”

In addition to Carson vs. Trump, an all-Florida fracas is brewing between former Gov. Jeb Bush and U.S. Sen. Marco Rubio. Both are competing for more establishment-minded voters and donors, and they hope to seize control if the outsider candidates fade come wintertime.

Rubio has taken hits for missing Senate votes as he spends more time on the campaign trail.

“As a Floridian, I’m a little disappointed, because he’s missing, like, 35 percent of his votes,” Jeb Bush Jr. said at an event hosted by the New York University College Republicans. “And it’s just, kind of, like, ‘Dude, you know, either drop out or do something, but we’re paying you to do something, it ain’t run for president.’ ”

The 44-year-old Rubio has painted a generational contrast with Bush, who was something of a political mentor to Rubio. But like Carson, Rubio and his camp have been less openly critical of his antagonist.

While the debates have produced star-turning moments from candidates such as businesswoman Carly Fiorina, perhaps their biggest effect has been on the flip side.

Somnolent performances from Wisconsin Gov. Scott Walker helped sink his candidacy, and U.S. Sen. Rand Paul of Kentucky has also struggled to break through in the televised forums, though he remains in the race.

“These debates are very similar to a PGA golf tournament,” said Georgia Republican consultant Chip Lake, who is unaffiliated in the primary race.

“You can’t win the tournament in the first or the second round,” Lake said, “but you can certainly play yourself out of the tournament with a bad performance.”