The blisteringly direct accusations brought the subjects of race and bigotry, previously undercurrents, to the surface of this year's presidential election. And the exchanges hinted at just how nasty the verbal battle between Clinton and Trump could become in the roughly 10 weeks until the general election.
Clinton's aim is to diminish Trump in the eyes of Americans uncomfortable voting for someone who appeals to racists, perhaps even winning over some moderate Republicans. Trump is fighting that image by appealing to minority voters while questioning Clinton's own record on race issues, noting that Democrats have long controlled urban cities where many African Americans continue to live in poverty.
While Clinton stopped short of accusing Trump directly of being a racist, Trump offered no such restraint with his remarks.
Clinton's speech yesterday afternoon, delivered at a community college in this general-election battleground state, focused particularly on Trump's connection to the alt-right.
It's a movement that predates Trump, but it was his presidential campaign that brought it into the mainstream. From the moment he told a national audience that Mexico was sending rapists and drug dealers across the border, Trump surged in the polls.
The movement has come under new scrutiny in the wake of a leadership shake-up in the Trump campaign that included the installation of Breitbart News head Steve Bannon as the campaign's chief executive. Bannon has described Breitbart News as "the platform for the alt-right". "The de facto merger between Breitbart and the Trump Campaign represents a landmark achievement for the alt-right," Clinton said.
"A fringe element has effectively taken over the Republican Party."
Clinton also called Trump "a man with a long history of racial discrimination, who trafficks in dark conspiracy theories drawn from the pages of supermarket tabloids and the far dark reaches of the internet".
In his own speech in New Hampshire earlier yesterday, Trump tried to discredit Clinton's argument before she had made it, calling it "one of the most brazen attempts at distraction in the history of politics" and an attempt to spread "smears and her lies about decent people".
"It's the oldest play in the Democratic playbook," he said. "When Democratic policies fail, they are left with only this one tired argument: You're racist, you're racist, you're racist. They keep saying it: You're racist.
"It's a tired, disgusting argument, and it's so totally predictable."
Trump framed Clinton's speech not as an attack on him but as an attack on the "millions of decent Americans" who support him.
He provided a point-by-point defence of some of his most controversial stances - including blocking refugees from entering the country, cracking down on illegal immigration and intensifying policing - saying that it is not racist, Islamophobic or hard-hearted to want to keep Americans safe.
"To Hillary Clinton and her donors and advisers pushing her to spread smears and her lies about decent people, I have three words, I want you to remember these three words: Shame. On. You," Trump said.
The fact that questions about race and bigotry dominated the day was by itself a victory for Clinton. She and her top aides have spent several days trying to fend off new questions about foreign donations to the Clinton Foundation and her use of a private email server during her tenure as secretary of state.
In a contest in which both Clinton and Trump are viewed unfavourably by wide swathes of the electorate, both are seeking to make the race a referendum on the fitness of the other.
In recent days, Trump has been aggressively trying to shed the label of racist, which his campaign and supporters say is unfair and unmerited. He has increased the number of minority surrogates speaking on his behalf on cable news and at his rallies, and he is planning to take trips into urban areas soon to visit churches, charter schools and small businesses in black and Latino communities.
The purpose of this pitch is not only to reach out to minority voters but also to soften Trump's image among white moderates, notably women, who have been taken aback by Trump's rhetoric. He has delivered the vast majority of his speeches to overwhelmingly white crowds, even when he appears in cities with large minority populations.
