Kamala Harris savaged Donald Trump as "extreme" and the friend of dictators, while the Republican branded her a "Marxist" in a bitter televised debate Tuesday that poured fuel on an already explosive US presidential election.
On hot-button issues ranging from abortion and race to the fate of US democracy, the two held their first -- and possibly only -- debate ahead of the November 5 election, with each hoping for a breakthrough in an agonizingly close race.
Trump, who only a few weeks ago had believed himself to be cruising to victory, reacted to pressure from Harris by raising his voice and resorting to the kinds of colorful invective and often meandering insults that he uses at his rallies.
Harris, 59, responded by looking on in amusement, then clearly got under his skin, declaring that she represents a fresh start after the "mess" of the Trump presidency -- and saying: "We're not going back."
The ABC News debate began when the Democratic vice president unexpectedly approached the Republican former president to shake his hand, before they took to their lecterns in the National Constitution Center in Philadelphia.
Then the niceties ended.
Within minutes, 78-year-old Trump called her a "Marxist" and also falsely claimed that she and President Joe Biden had allowed "millions of people pouring into our country from prisons and jails, from mental institutions and insane asylums."
Harris pointed out that Trump is a convicted felon, called him "extreme" and said it is "a tragedy" that throughout his career he had used "race to divide the American people."
One of their most jarring exchanges was on Trump's unprecedented refusal to accept losing to Biden in the 2020 election, before trying to overturn the result.
In front of the audience expected to run into the tens of millions of voters, Trump doubled down, insisting there is "so much proof" that he really won.
Harris turned to Trump and said that his own former security officials in the White House have called him a "disgrace."
"World leaders are laughing at Donald Trump," she said.
Trump would "give up" Ukraine to Russian leader Vladimir Putin, "a dictator who would eat you for lunch," she charged. "Dictators and autocrats are rooting for you to be president again."
Another intense exchange was on abortion.
Trump insisted that while having pushed for the end of the federal right to abortion, he wanted individual states to make their own policy.
Harris said he was telling a "bunch of lies" and called his policies "insulting to the women of America."
- Harris mocks Trump rallies -
The last presidential debate in June doomed Biden's reelection campaign, after he delivered a catastrophic performance against Trump. Harris took over as nominee amid Democratic fears that Biden was too old and infirm to defeat the scandal-plagued Republican.
Harris has earned a reputation in past debates and while serving as a US senator for ice-cold put-downs and tough questions.
Her five days of intensive preparation appeared to pay off against Trump, perhaps the most brutal public speaker in American politics.
Trump has long defied political gravity by seeming invulnerable to usual attacks.
He has been convicted of falsifying business records to cover up an affair with an adult film star, found liable for sexual abuse, and faces trial on charges of trying to overturn the 2020 election.
But Harris clearly needled him on one of his favorite, if less serious topics -- his trademark rallies.
Attendees, she said, prompting an angry retort, were leaving early out of "exhaustion and boredom."
At another moment where Trump appeared to be losing his cool, he talked at length about a debunked conspiracy theory that Haitian immigrants have been eating local people's pets in Ohio.
"They're eating the dogs, the people that came in, they're eating the cats," he said before being corrected by the ABC News moderator that the authorities in the town of Springfield have said this did not happen.
With only 56 days left before the election, the intense spotlight was a rare opportunity for both candidates to shift the balance in what polls show is an almost evenly split contest.
And the debate was a key chance for Harris to introduce herself to more voters after only jumping into the race less than eight weeks ago, when 81-year-old Biden abruptly quit.
