'This Week' Transcript: Dr. Ben Carson and General John Allen

— -- THIS IS A RUSH TRANSCRIPT.

(BEGIN VIDEOTAPE)

ANNOUNCER (voice-over): Starting right now on ABC, THIS WEEK, slugfest: Donald Trump under fire and firing back. Days before that make-or-break debate.

Plus the results of our brand new poll.

And could a new front-runner emerge? Trump's surprising top challenger, Dr. Ben Carson is here.

Will he or won't he? The gut-wrenching decision, the raw emotion, Vice President Joe Biden's brand new signals about a possible run for the White House.

And refugee controversy: urgent calls for America to help these desperate families. Is it time for the U.S. to do more? Or will it risk our security?

UNIDENTIFIED MALE (voice-over): From ABC News, THIS WEEK with George Stephanopoulos begins now.

(END VIDEOTAPE)

MARTHA RADDATZ, ABC HOST: Good morning. I'm Martha Raddatz. We begin with 2016. It's your voice, your vote.

And some astonishing numbers in our brand new ABC News "Washington Post" poll, revealing just how tight the race is between the front-runners. Take a look: in a Hillary Clinton-Donald Trump matchup, Clinton is in front but statistically they're essentially even, Clinton with 46 percent, Trump with 43 percent. And perhaps just as striking, a stunning gender gap for both candidates, Trump winning men by 15 points, Clinton up by 21 points among women.

Meanwhile, a key question this morning: with a critical GOP debate just three days away, can Donald Trump keep his front-runner status? Or is someone else ready to steal the spotlight?

It won't be Rick Perry, who, Friday, became the first to drop out but it could be Dr. Ben Carson, another outsider, now surging in the polls and taking new shots at Trump.

Dr. Carson will join us shortly. First, the latest from ABC's Jon Karl.

(BEGIN VIDEOTAPE)

UNIDENTIFIED MALE: I'm a Reagan conservative.

JONATHAN KARL, ABC NEWS CHIEF WHITE HOUSE CORRESPONDENT (voice-over): Republicans will no doubt pay tribute to the Gipper when they assemble at the Reagan Library for this week's debate. But these candidates have shredded Reagan's 11th commandment: thou shalt not speak ill of any fellow Republican.

Speak ill? What do you call this?

Frontrunner Donald Trump on Carly Fiorina and "Rolling Stone" magazine. Look at that face.

Would anyone vote for that?

And the backlash that provoked.

CARLY FIORINA (R), PRESIDENTIAL CANDIDATE: But maybe, just maybe, I'm getting under his skin a little bit because I am climbing in the polls.

UNIDENTIFIED MALE: This disparaging of women is deeply troubling.

KARL: Bobby Jindal, languishing at the back of the pack, threw the book at Trump, a thesaurus.

GOV. BOBBY JINDAL (R-LA), PRESIDENTIAL CANDIDATE: Trump is a narcissist and he's an egomaniac, insecure and weak.

KARL: Even the soft-spoken Dr. Ben Carson, who soared in the polls to become a close second to Trump, got into the act, questioning Trump's commitment to God.

DR. BEN CARSON (R), PRESIDENTIAL CANDIDATE: That's a very big part of who I am, humility and fear of the lord. I don't get that impression with him.

KARL: Trump then went nuclear on Carson, calling him boring, heavily involved in abortion, which is not true, and even questioning the renowned brain surgeon's medical record.

TRUMP: He's overrated as a doctor.

KARL: One Republican did try embracing Trump this week. Ted Cruz inviting "The Donald" to the rally against the Iran nuclear deal in DC. But Cruz told us the real reason.

(on camera): Why did you have Donald Trump in this rally?