After Hillary Clinton attacked Donald Trump for proposing to bar Muslims from entering the United States, calling him "ISIS' best friend," Trump's response Monday night was angry and vulgar. He said her bathroom break during Saturday's Democratic debate was "disgusting," and he used a crude sexual reference to describe her defeat by Barack Obama for the 2008 nomination.
Clinton's aides could barely believe their good fortune. Trump had just given them new fodder to galvanize women behind her candidacy — and they used it.
"We are not responding to Trump," Clinton's communications director, Jennifer Palmieri, responded to Trump, almost gleefully, on Twitter. "But everyone who understands the humiliation this degrading language inflicts on all women should," she added, tacking on the campaign's girl-power hashtag #ImWithHer.
Behind the scenes, the Clinton campaign mobilized a wide network of female supporters to denounce Trump as "sexist," as a practitioner of "pathetic, frat-boy politics," and as more suited to running for "president of the fourth-grade football team."
For months, Clinton's strategy was to hang Trump's more outrageous pronouncements around the necks of other Republican contenders, seeking to portray the party's entire field as extreme. But by going after Trump more assertively now than most of his Republican rivals have dared, Clinton is projecting strength, and she is calculating that women, especially young voters, will reward her.
In an interview with The Des Moines Register late Tuesday, Clinton said of Trump, "It's not the first time he's demonstrated a penchant for sexism."
Combativeness, after all, plays into Clinton's campaign theme: The blue "Hillary" signs that blanket her rallies carry the slogan "Fighting for You" in big block letters.
But poking at Trump is not risk-free. He is unlike any rival Clinton has confronted before, and has proved willing to say almost anything.
On Wednesday night, Trump posted a cryptic warning shot at Clinton on Twitter. "Hillary, when you complain about a 'penchant for sexism,' who are you referring to," he wrote. "BE CAREFUL."
On Tuesday, Clinton's allies continued to join the fray: Emily's List, which raises money for female candidates who support abortion rights, released an open letter calling on other Republican candidates to denounce Trump's remarks.
"You have a chance to step up and do something about Donald Trump," the letter read. "Most of you are, frankly, a lot smarter than he is. You at least know enough to try to hide your anti-woman policies behind the nice things you say about the women that you know."
The comments by Trump in Michigan on Monday night, and the Clinton campaign's aggressive response, rattled some in the Republican Party, whose leaders urged candidates to show more sensitivity to women after Rep. Todd Akin provoked ire in 2012 for referring to "legitimate rape."
"It's not OK," said Katie Packer Gage, a Republican strategist whose firm, Burning Glass
Consulting, focuses on improving the party's standing with women. "Guess what?" she added, "It takes a girl longer to go to the bathroom because they can't go standing up. Polite society suggests we don't talk about these things."
The Clinton campaign's emboldened new posture toward Trump grew from months of watching how his Republican rivals struggled to challenge him.
While the other candidates for the Republican presidential nomination tread carefully to avoid antagonizing Trump's numerous supporters, for Clinton, hitting hard offers immediate benefits.
It shows that she is unafraid of him, Democratic strategists said. And by focusing on Trump's more extreme comments, Clinton could excite the growing list of constituencies he has directly offended — as well as a broad range of voters who see Trump as a corrosive presence in the presidential campaign.
"The contrast between her and Donald Trump could not be clearer," Clinton's campaign manager, Robby Mook, said after Saturday's debate.
"The more Trump is out there," he added, "the more these differences are clear, and what's at stake for the middle class, both in the economy and in defeating ISIS."
Clinton's assertion in the debate that the Islamic State was "showing videos of Donald Trump insulting Islam and Muslims in order to recruit more radical jihadists" amounted to something of a turning point.
Though journalists and Republicans found no evidence of such videos, Clinton's aides refused to take back her assertion. Trump, so often called on to admit to a falsehood or apologize, demanded a retraction from Clinton.
"Hell, no," Brian Fallon, a spokesman for Clinton, replied.
Kellyanne Conway, a Republican pollster who heads a super PAC supporting Sen. Ted Cruz of Texas, said she saw advantages in Clinton's failure to back up her assertion about militants using Trump's comments as a recruitment tool.
"Polls show a majority of Americans believe that Mrs. Clinton is not trustworthy," Conway said. "Telling a lie feeds the fire and opens a new front in the character wars."
She added, "Swing voters won't care that she took a bathroom break, but they will care that she seems willing to say anything to get elected."
Republican candidates were quick to defend Fox News anchor Megyn Kelly after Trump seemed to suggest that she had been unfairly tough on him during a debate because she was menstruating. But so far, party insiders have mainly demurred from criticizing Trump's latest boundary-breaking remarks, since publicly defending a Democratic rival, even if it appeases female voters, could prove problematic.
Sen. Rand Paul of Kentucky even joined in the mockery. "Carly Fiorina has ZERO trouble making it back from commercial breaks," he wrote in a Twitter post that Fiorina, who has had her own run-ins with Trump's gendered attacks, promptly retweeted.
Even some Democrats cautioned that Clinton should not get carried away with combativeness toward Trump.
"Long-term, we need to be careful of not unifying the Republicans" against Clinton, said Stephanie Cutter, a former senior adviser to Obama, "when they're doing a good job of knifing each other."