Men are abandoning Trump in droves

Jay Laprete | AFP | Getty Images

A supporter of Donald Trump at a campaign rally in Toledo, Ohio on October 27, 2016.

This commentary originally appeared on The Hill.

When Cecile Richards, president of Planned Parenthood, told GOP nominee Donald Trump from the podium of the Democratic National Convention in July that "women are gonna be the reason you're not elected to be president," she probably didn't forsee a sinking ship of this magnitude.

Trump's terrible October began Oct. 7, when an 11-year-old video from "Access Hollywood" came to light. In it, Trump describes his past sexual assaults of women: "I don't even wait."

This was followed by a line of women who have come forward, describing events where, they claim, Trump actually sexually assaulted them (Trump denies these stories are true). New York magazine lists over 20 allegations of Trump's mistreatment of women that have come out in the past month. And the list grows.

More from The Hill:
Clinton fails to contain the damage from email leaks
Trump losing cash race in final weeks
Clinton comes under pressure from left in campaign's homestretch

Add to all of that the three public debates where the public consensus seems to be that Clinton bested Trump, three out of three.

October was a terrible month for candidate Trump among women, one might think.

Few were shocked when an ABC/Washington Post poll, taken between Oct. 20 and Oct. 22 by Langer Research Associates, was released, trumpeting a headline that Clinton was now in advance of Trump by 12 percentage points nationally among likely voters.

That's what the poll — a snapshot in time — says.

But look at the movie, see where the action is, and a different picture emerges.

Comparing two ABC/Washington Post polls taken a month apart, Trump's disaster of October didn't occur among women, the majority of whom already supported Clinton.

Trump's disaster occurred among his base: men.

In the first poll taken Sept. 19-22 — before the "Access Hollywood" video came out — Trump was favored over Clinton by 19 points among all men, a huge advantage for Trump, which reflects the historical advantage Republicans have had with men in presidential elections.

But by the late October poll, the results had flipped. Democratic nominee Hillary Clinton now leads Trump by 3 points in the same group — a swing of 22 points — roughly equivalent to one in five men ending their support for Trump during the past month.

That's a huge swing. One might expect that there is a similarly large swing among women; perhaps larger. But there isn't.

In September, women favored Clinton over Trump by 19 points; come October, that advantage did not measurably increase. A mere 1 point changed — It's now 20 points — minuscule in comparison to the 22-point swing among men.

What happened?

The impact was greatest among white men without a college degree. These men are supposed to be Trump's base — and indeed, they still are the largest single demographic that supports Trump, according to the October poll.

But comparing the September and October polls, one sees Trump's base is abandoning him.

In September, Trump enjoyed being 59-point favorite over Clinton among this demographic, but by October, this lead had shrunk to only 31 points — a change equivalent to Trump losing support of one in four white blue-collar men in October.

That's an abandonment. That's an evaporation.

There can be more than one explanation for this change. First, it could be that men are abandoning the Trump ticket, and switching to Clinton in droves. A second possibility lies in that "likely voter" qualifier — it could be that men are simply abandoning Trump; and even if they are not pledging themselves to vote for Clinton in November, they've removed themselves from among likely voters, thus changing the outcome.

There's a third possibility: The men are lying to the pollsters. The polls were taken by phone, so one might expect the poll subjects were at home, or at work, perhaps in the presence of their spouse. In early October, an article in The Week describes that 12 percent more wives are voting for Clinton than thought by their male spouses.

Likewise, 8 percent more husbands are voting for Trump than thought by their female spouses. Spouses are deceiving each other, perhaps to keep the peace at home.

And, so, in the wake of Trump's awful behavior coming to light, more blue-collar men might be finding it difficult to assert that they're voting for Trump while they're on the phone with a pollster with their wife sitting nearby, even if their intention for the privacy of the ballot box is different. We won't know for certain until a poll that isolates the subjects, or until Election Day.

But if we accept these polls for what they say, the conclusion is clear: There has been an enormous swing from Trump to Clinton among men in the past month, a swing largely due to an evaporation among Trump's base: white men with no degree. And while white women have also moved from Trump toward Clinton, the migration has been smaller in comparison.

White blue-collar men have been, and continue to be, Trump's base. But, his base has abandoned him in October in such numbers that, if he weren't so loudly denigrating her, Trump might hear the fat lady sing.

Commentary by Robert E. Rutledge, a Hill contributor and an associate professor in the Department of Physics at McGill University in Montreal, Québec, Canada.

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.