WASHINGTON (AFP) - The tone of the United States presidential campaign turned darker on Thursday (Aug 25), with Democrat Hillary Clinton skewering billionare Donald Trump as a man who flirts with racism and paranoid ideas, while he in turn labelled her a racist whose family foundation was a "criminal enterprise".
Speaking at a campaign event in Reno, Nevada, Mrs Clinton employed unusually tough language as she detailed a history of what she said were the Republican real-estate mogul's discriminatory actions.
He had been sued as a young developer for failing to rent to black and Latino tenants, and by black employees of his casinos, the Democratic presidential candidate said.
The Republican nominee's recent choice of Mr Steven Bannion, a firebrand conservative, as his new campaign chief showed Mr Trump was embracing the extremist white nationalist stances of the so-called "alt-right" movement, she said.
"A man with a long history of racial discrimination who traffics in dark conspiracy theories drawn from the pages of supermarket tabloids and the far dark reaches of the Internet should never run our government or command our military," Mrs Clinton said.
Her speech came on a day when one poll showed her support reaching an important threshold - backing from just over half of all respondents. The survey by Quinnipiac University gave her a 51 per cent to 41 per cent lead over Mr Trump in a head-to-head race.
Mr Trump has recently attempted to enlarge his tiny base of support among blacks - it has been as low as 1 per cent - arguing that African-Americans have "nothing to lose" by voting for him.
He met with a group of black and Latino supporters at his Trump Towers in New York early on Thursday.
Speaking in New Hampshire later, Mr Trump lashed out at Mrs Clinton, saying she was accusing "the decent Americans who support this campaign, your campaign, of being racists, which we're not".
Calling it "a tired, disgusting argument", he said it was Mrs Clinton who was being a "racist" by viewing minorities merely as a source of votes while doing nothing for them.
Mr Trump also sought this week to moderate his earlier comments on immigration.
As president, he would focus on deporting the "bad" immigrants without uprooting the "good" ones, he said - a sharp shift from his early insistence that all undocumented immigrants be deported.
Somewhat confusingly, however, he insisted again on Thursday that he would build a wall on the southern border and make Mexico pay for it.
Giving in to the persistent urging of party leaders, Mr Trump has begun relying more on a TelePrompter, allowing for fewer troublesome off-the-cuff remarks.
That new discipline has enabled the Republican tycoon to concentrate his attacks on Mrs Clinton and his allegations that, as secretary of state, she trafficked in influence through the family's Clinton Foundation.
Recently released e-mails showed that donors to the foundation had been given greater access to Mrs Clinton and her staff, he said.
"This week the curtain was truly lifted," he said. "The corruption was revealed for all to see. The veil was pulled back on a vast criminal enterprise run out of the State Department by Hillary Clinton."
Mrs Clinton, who has denied the influence charges, pressed the argument that Mr Trump lacks the temperament to be president.
"Donald Trump has built his campaign on prejudice and paranoia," she said. "He's taking hate groups mainstream and helping a radical fringe take over the Republican Party.
"His disregard for the values that make our country great is profoundly dangerous."