As Republican notables denounce or distance themselves from Donald Trump in the wake of his latest controversy, the world watches and asks, "Why now?"

Put another way: Why is this incident different? What is it about this latest evidence of Trump's nature and views that's truly more unacceptable than all the preceding information on the subject? How can the Republican nominee, who has been his party's front-runner for nearly a year, suddenly be regarded as utterly beyond the pale?

Blame the substance, the tape, the timing or the "tipping point," but the surge of Republican desertions happened because Trump's offense hit them where they live — both personally and politically.

Language, Timing, And The Power of Video

Questions about "why now" have already prompted an array of responses. We all know about the straw that broke the camel's back; but this particular camel's back has proved remarkably durable. Most of us want more of an explanation than this.

Some point to the power of videotape. Released Friday by the Washington Post, the 2005 tape shows Trump telling TV host Billy Bush how he tried to seduce Bush's Access Hollywood co-host — and bragging in the crudest language about other sexual forays. If you have not heard or seen it, there is little point in further discussion. If you have, you are altered by it. This is not just another gotcha report, another media yarn. It becomes part of everyone's own lived experience of Trump.

Others note the distinction between mere words about sex and the nature of the deeds in question. Although Trump is bragging about his behavior, the aggressive sexual encounters he describes amount to a level of sexual assault. In many states, they could be punishable with imprisonment. For many Republican officials and other notables, this is not a tipping point but a breaking point.

There is also the matter of timing. The audio came out just days before Sunday's pivotal debate between Trump and Democratic nominee Hillary Clinton at Washington University in St. Louis.

Even before the Friday night release of the videotape, this second in the series of three debates was regarded as crucial for Trump. While he disputes the notion, scientific polls and commentators have been nearly unanimous in saying he did poorly in the first debate on Sept. 27. That event and the events of the following 10 days restored Clinton's clear lead in the average of national polls and in the swing states. The emergence of this tape at this time could scarcely be more portentous.

All these explanations have some validity, but they do not tell the whole story. It's also about politics and empathy.

The Politics

In offices, schools and homes all over the country, women seeing the videotape gasped, jumped, cried out, lost their composure. It seemed to matter on a level all its own.

But there is a cooler calculation involved here as well. And it is important to note. Others Trump may have offended in the past have tended to be voting groups where he has had little appeal. They are not especially fertile fields for Republican politicking. Even when Trump has gone to black churches or "reached out" to minorities, the gesture has been seen primarily as an appeal to someone other than those minorities themselves.

The real object of the outreach has been the swing votes of white moderates, especially the highly prized demographic of white non-Hispanic women in childbearing and child-rearing years. They were first called "soccer moms" in the 1990s, then "security moms" in the aftermath of the terrorist attacks of 2001. They have often been called "working moms," too, whether they had jobs outside the home or not.

They were seen as crucial to the popular-vote victories of Bill Clinton and Al Gore, then to the re-election of George W. Bush in 2004. They were a key for Barack Obama in 2008 and 2012. In the current election cycle, the shorthand for their bloc has shifted to "suburban white women." But whatever they are called, Trump needs them desperately.

Trump's rock-bottom numbers among nonwhite voters mean he must do better among white voters than Mitt Romney did in 2012 (59 percent according to exit polls). Trump may need 65 percent or more of the white vote to win. He does better than that among white men, but he needs to break even (at least) among white women.

Right now, younger white women are trending to Clinton, their older counterparts to Trump. The battle is in the middle.

It is Trump's battle for this election in this moment. But it is the Republican Party's battle for every other office this fall and every election hereafter.

That is why more Republican senators came out against Trump in the last 48 hours than in the six months since he became their party's standard-bearer. Not just female senators, such as Deb Fischer in Nebraska and Lisa Murkowski in Alaska, but several of the men who had been holding out as well.

Principal among them was John McCain, seeking a sixth term in the Senate at age 80. McCain was personally insulted by Trump in the summer of 2015, yet had maintained a strained neutrality toward him ever since. Despite all the slings and arrows of this campaign year, McCain refused to say he wouldn't vote for Trump.

On Saturday, he did so. He knows perfectly well it will cost him some votes next month among Trump supporters. But he also knows his party has been alienating Hispanics (30 percent of Arizona's population) and cannot afford to add more Anglo women to the list.

It is a dilemma the GOP cannot wish along so long as Donald Trump stands as their champion.

The Personal

Trump knows that getting personal is an effective political tactic. When he wanted to hammer home his anti-immigration message, he brought onstage parents of people killed by immigrants in the country illegally. They put a human face on the anger he expressed when he promised to "build the wall."

But getting personal has also gotten him in a lot of trouble. Trump's Muslim ban alarmed some of his fellow Republicans, but he drew some of his sharpest rebukes when he feuded with the Khan family. Trump's rhetoric had already upset many Hispanic voters, but Paul Ryan called it " racist" when Trump said that Judge Gonzalo Curiel couldn't be an impartial judge because he was of Hispanic heritage. There was always evidence of Trump objectifying women in the past, but people took extra notice when he specifically referred to Megyn Kelly, saying there was "blood coming out of her eyes, blood coming out of her wherever," as well as when they were reminded of his past comments about former Miss Universe Alicia Machado's weight.

What may have happened this time is that it got too personal. True, Trump didn't list the names of women he seemed to be bragging about kissing and grabbing. However, he seemed to be talking about personally violating other living, breathing people with his own hands — something that goes beyond words or policies potentially affecting someone.

(And while it may have been "locker room talk," as his campaign put it, and we can't be sure he has acted on those words, women have come forward alleging that he did these exact things — one beauty pageant contestant says he kissed her unwantedly, and a former business partner said he touched her crotch, again unwantedly.)

And this seems to be turning many top Republicans away from him, as evidenced by the fact that many Republicans' statements denouncing him mention mothers and sisters and daughters. Suddenly, Trump's words became hyperreal, and people imagined themselves or the women they knew being groped.

There's potentially something to be gleaned here from the famous trolley thought experiment, in which a trolley is hurtling towards five people on the tracks, but has the option of diverting onto a separate track on which there is only one person. Given the choice to pull a lever and divert the trolley, killing that one person, many people say yes.

However, there is a different variant, in which the only way to stop the trolley is to push a large man in front of it. To many people who would pull the lever, this nevertheless feels wrong, even though it would make for the same body count.

To be clear, the analogy is not fully applicable; there's no person on the tracks in the Trump situation. But the point is purely that once he crossed the barrier of talking about physically violating people, that is when his peers suddenly decided he had crossed a red line.

"This is the kind of action that typically provokes a strong emotional response, and for reasons similar to those at work in trolley dilemmas," Joshua Greene, a Harvard professor of psychology who has studied how people answer the trolley problem, told NPR. According to him, there are four different reasons why people usually refuse to shove the man onto the tracks, and the kissing-and-grabbing scenario Trump described fulfilled all four.

"It's an active, direct, specifically intended, bad thing" that Trump seemed to be bragging about doing, Greene said.

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