10/19/2016 10:56 EDT | Updated 10/19/2016 10:56 EDT

U.S. Presidential Candidates Face Off In Final Election Debate

The election is less than a month away.

WASHINGTON — The final U.S. presidential debate featured a passionate exchange over the Russian role in the current election, with candidates accusing each other of being potential puppets of Vladimir Putin.

The exchange started when the moderator Wednesday raised emails hacked from the Democratic campaign, which include a transcript of Hillary Clinton telling a bank that she dreams of open borders and free trade.

Clinton responded in passing that she was referring to trade in energy. She then turned the subject to the emails themselves. She noted that numerous intelligence agencies have accused Russia of stealing emails and posting them on Wikileaks, in what she called an unprecedented effort by Putin to influence a U.S. election.

"That's because he'd rather have a puppet as president of the United States," Clinton said.

Republican presidential nominee Donald Trump waits behind his podium as Democratic presidential nominee Hillary Clinton makes her way off the stage on Oct. 19. (Photo: David Goldman/The Associated Press)

"He has a clear favourite in this race. ... I find that deeply disturbing."

Trump shot back: "No puppet. You're the puppet." When pressed on whether he believed American intelligence agencies, Trump said he doubted them.

Trump entered the third and final debate facing the monumental task of turning around this presidential race, confronting the forces of history, electoral mathematics and his deep personal unpopularity.

Nobody in the era of modern opinion polling has recovered to win the presidency when trailing by such margins at this late stage in the race, with the election in less than three weeks and advance voting already underway.

It began with substantive exchanges over abortion, gun control and immigration — places where the candidates differ. Trump wants to appoint anti-abortion judges and allow states to decide the issue. He accused Clinton of favouring late-term abortions — which he called ripping babies from the womb. Clinton countered that late-term abortions are often the result of medical emergencies and said the government should butt out.

"We have some bad hombres here."

They sparred on immigration.

Clinton derided the idea of deporting millions of undocumented people, splitting up families and sending them away on trains and buses. Trump countered by referring to his four guests in the audience related to people killed by undocumented immigrants.

"We have some bad hombres here," Trump said, using the Spanish word for "men."

"And we're gonna get 'em out."

Trump disputes polls showing him losing. He says the media only hype the bad ones for him. There is no shortage of so-called bad ones. Of the last 25 national head-to-head polls compiled by the website RealClearPolitics, Trump led just one. Clinton's margin of victory had grown to an average of about seven percentage points.

Wednesday was likely his final campaign opportunity to speak to a prime-time audience of this size.

Donald Trump gestures as Democratic nominee Hillary Clinton looks on during the final presidential debate. (Photo: Robyn Beck/AFP/Getty Images)

The first two debates didn't help.

Every scientific survey conducted afterward suggested viewers felt he lost. He bragged about not paying taxes, allowed Clinton to draw him into a multi-day feud with a former Miss Universe and threatened to jail his rival — all in front of invited guests that included several women known for having accused Bill Clinton of sexual assault.

While ardent Trump fans profess their support on unscientific online surveys, more credible polls show there is resistance to his candidacy from one important group of Americans — suburban women.

One poll from Fox News this week shows him losing suburban women by a whopping 24 per cent gap, causing him to trail significantly in the suburbs — which Mitt Romney won. He has cast himself as a change agent, but there are two sizeable obstacles on that path.

Every poll suggests the self-styled change agent is less popular than the current president. Second, the Fox survey suggests that when respondents are asked who'll deliver the best change, he's three per cent behind Clinton.

The other disheartening news for Trump is that third debates tend not to matter much. Historically, they have drawn the smallest audiences, and made the tiniest impact on voting intentions.

Fivethirtyeight.com compared polls before and after debates and found the numbers usually shifted less than one percentage point following the third debate, with the rare exception of 1992 when third-party spoiler Ross Perot had a big impact.

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