One grew up poor in inner city Detroit and went on to become a renowned neurosurgeon. The other received a "small loan" of $1 million from his father to go into the family business.
One has insulted his rivals -- and Mexican immigrants and women and Seventh-day Adventists and Iowa voters and POWs. The other rarely takes shots at fellow Republicans.
And where Trump once referred to the communion wafer as a cracker, Carson speaks about his faith with ease, wrapping his biography in the language of deliverance. His cultural broadsides—about Muslims and homosexuals and Nazi Germany—are delivered with a calm, matter-of-fact manner rather than high-octane bluster.
They are Trump and the anti-Trump. Or Carson and the anti-Carson. And they are the GOP presidential front-runners.
For the first time, Carson leads Trump in Iowa and edges him in a new national poll
, suggesting that he may be poised to topple Trump, who has dominated every survey since the summer. According to a New York Times/CBS poll released on Tuesday, 26% of GOP primary voters support Carson and 22% back Trump — the 4 point gap is within the margin of error.
Three consecutive polls of GOP caucus goers in Iowa show Carson with a clear edge -- evangelicals and women are shifting his way.
It's unclear whether Carson is enjoying a brief run at the top of the polls or whether he'll be able to translate the energy surrounding his campaign into a sustainable lead like Trump has for months. Either way, the candidate with an answer for everything is suddenly off his game.
"I don't get it," Trump told MSNBC's "Morning Joe" Tuesday morning.
While Trump's taunts have rattled opponents, he has yet to land on an insult for Carson, who is the most well-liked GOP contender. Carson, who has been on book tour for the last few weeks, has built up a successful brand among a core Republican constituency that will be hard to muddy.
Trump has trotted out the low-energy knock on Carson, but the retired pediatric neurosurgeon shot back by highlighting what people like best about him — his niceness and his medical background.
"Everybody has their own personality. If you like to do that, that's fine. That's not who I am. And I don't get into the mud pit. And I'm not going to be talking about people," he said this weekend on NBC's "Meet the Press." "I will tell you, in terms of energy, I'm not sure there's anybody else running who's spent 18 or 20 hours intently operating on somebody."
Trump also seemed to suggest that Carson's faith—he is a member of the Seventh-day Adventist church—is outside of the mainstream. Yet evangelicals, whose support has helped Carson vault ahead of Trump, are familiar with his faith-centered life story, outlined in his memoir, "Gifted Hands."
"That's a crowd that has always been favorable to him," said Ryan Rhodes, who is overseeing Carson's campaign in Iowa. "A lot of home school people learned Ben's life story in school and they reach out to us and want to support the campaign."
Carson's biography and recent statements are resonating with voters -- particularly in Iowa. A Bloomberg/Des Moines register poll showed that a majority of GOP caucus voters agree with his stance on a Muslim president and his statements about Nazi Germany and gun control.
And in a party that has yet to see a non-white person — or a woman — win a state in a presidential contest, Carson's race also makes him an attractive candidate.
"Conservatives are used to hearing three things over and over again: that they are racists, that they are bigots, and that they aren't very bright," said Ben Domenech, publisher of The Federalist, a conservative online magazine. "His race, faith, and intelligence all satisfy conservative desires to push back against current negative ideas about who Republicans are."
Carson has spent the last few days in West Palm Beach, Florida, prepping for Wednesday's debate, which will focus on the economy. Aides said that Carson is prepared to challenge Trump, whose strength is the economy and his business background. They are also mindful of past cycles, where good poll numbers and Iowa wins have yielded only flavor-of-the-month results and regional candidates.
"It's just a reminder that we make progress every week but it can change on a dime. People have to believe in a message and relate to it and connect to it," said Armstrong Williams, Carson's business manager. "You don't just prove yourself because you are up in the polls. We realize they can change and we are prepared for that."
Still, Carson's dominance in a string of polls has also done something that Jeb Bush's counterattacks against Trump haven't done — they have deflated the billionaire businessman and taken away one of his biggest talking points.
"If you're Donald Trump and you come out and you act as if you're going to win everything all the time, you're going to lead every poll all the time—when you do start to fall, it is a bigger deal than if you're up and down and up and down or tight race," said Ben Ferguson, a conservative commentator on CNN's Erin Burnett Out Front. "Ben Carson has played this brilliantly. He has not said or gloated about polls. You rarely hear him talk about these poll numbers. Donald Trump, you hear about it every time he walks up on stage."