This article has been edited and updated from an earlier version with the latest numbers from the Presidential Poll Tracker.

Donald Trump's worsening position in the polls was sparked by his poor performance during the first presidential debate and has been sustained by a torrent of problems dogging his campaign — including the emergence of allegations of inappropriate behaviour or sexual assault from about a dozen women.

Tonight's third and final presidential debate may be Trump's last opportunity to turn things around. And it's women — for whom Trump says he has "great respect" — who might just be the most significant obstacle to his White House ambitions.

According to the CBC's Presidential Poll Tracker, Hillary Clinton now holds a lead of 6.9 points over Trump. In recent days she has opened up the widest margin she has enjoyed over the Republican nominee since they clinched their respective parties' nominations in June. Clinton is holding 48.3 per cent support among decided voters in a weighted average of national polls, against 41.4 per cent for Trump.

Two days before the first presidential debate on Sept. 26, Trump had closed the gap with Clinton to just 1.7 points. But since then, Clinton's lead has steadily grown by three points, while Trump's support has slipped by two points.

The chart above shows how recent events have had an impact on Trump and Clinton — but also how those impacts take some time to be reflected in the polls, both because polls are taken over multiple days and because the repercussions of an event can take several days to fully filter down to the electorate.

The positive movement for the Democratic nominee has improved her position in the electoral college dramatically. Though she was still leading in the electoral college projections (as she has done throughout this campaign) on the eve of the first debate, enough swing states were on the bubble that she could have dropped to as low as 214 electoral college votes, and Trump as high as 324, if things went badly for her.

Now Clinton is leading in enough states to give her between 279 and 374 electoral college votes, above the 270 votes needed to win the presidency. Trump's range has slipped to between 164 and 259.

Utah and Arizona, swing states?

Despite Clinton's growing national lead, a number of states remain virtual toss-ups. She is ahead by just two points in North Carolina, three points in Florida and four points in Nevada. In Ohio, she is up by just a few tenths of a percentage point.

Nevertheless, even if Trump won all of these swing states, he would still be a few electoral college votes shy of the White House.

He would then need to capture another state, such as Pennsylvania, Colorado, Minnesota or Wisconsin. The problem for Trump is that he is at least seven points behind in all four of these states.

But Clinton is behind by similar or smaller margins in solidly Republican states like Georgia (two points), and Missouri and South Carolina (seven points). She also trails in Arizona by just one point. 

Four years ago, Mitt Romney won all of these states by eight points or more in a losing national campaign.

Romney also won Utah by 48 points. The majority-Mormon state has not looked kindly on Trump's recent statements and the allegations against him. Four recent polls have showed his support dropping to between 28 and 42 per cent among decided voters, with much of that lost vote going to independent conservative candidate Evan McMullin, who has polled between 20 and 29 per cent.

Clinton, polling in the 28 to 30 per cent range, is not likely to win Utah. But a competitive, unpredictable three-way contest in Utah, of all places, could be just one of the oddities on election night in this already unusual election campaign.

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Women (not) for Trump

A common sight at Trump's boisterous rallies are scores of women carrying "Women for Trump" signs. But the polls suggest that this is a shrinking group, as Clinton — the first female presidential nominee of a major party — has opened up an enormous edge over Trump among women.

An average of four recent national polls that published detailed demographic data (Monmouth, CBS/New York Times, Morning Consult and Fox News) and that were conducted after the second presidential debate, when the sexual assault allegations started making headlines, shows Clinton enjoying a lead of 16 points among decided female voters (53 to 37 per cent) — compared to a tied race among men (43 per cent apiece).

Campaign 2016 Trump

Trump supporters (from left) Mary Claire, Colette McDonald and Karolee McLaughlin in Boulder, Colo. (Paul Aiken/Associated Press)

But while Trump's deficit among women is significant (and would be among the largest in American electoral history), it is not clear that his lewd comments in a 2005 video and the sexual assault allegations against him have had a disproportionate impact among female voters.

Clinton's advantage among female voters has only widened by an average of three points since these details emerged, according to the four pollsters. However, among men, Clinton has erased the eight-point lead Trump held.

It should not come as too much of a surprise if Clinton's recent gains have come largely from men — she had more room for growth among male voters than she did among women, many of whom had rejected Trump long before the latest controversies. But it also seems likely that these controversies will make it very difficult, if not impossible, for Trump to make up any ground among the female half of the electorate.

When talking about Clinton's chances of winning the presidency, much has been made of so-called firewall states, like Virginia and Pennsylvania, that block Donald Trump's path to the White House. But that firewall might prove to be much larger than just a handful of states.

And it might be manned primarily by women.