A shocking national poll released Wednesday morning shows the U.S. presidential race as a statistical dead heat, with Democrat Hillary Clinton's lead over Republican Donald Trump shrinking to just 2 percentage points, a number that's within the survey's margin of error.

The respected Quinnipiac University poll found Clinton with a 42-40 lead in a hypothetical head-to-head matchup, narrowing from a 4-point gap a month ago.

But neither candidate has anything resembling a national vote of confidence. Fifty-eight percent said Trump would not make a good president. Fifty-three per cent said the same of Clinton.

Clinton has led in all 22 of the national election polls published since mid-May, in some cases by as many as 12 points. The 'Q-poll' result suggests some of her most recent romp may have been an extended Hillary 'bounce' – which is now boomeranging back – related to her long-awaited primary victory over Sen. Bernie Sanders.

LOOK OUT: Hillary Clinton's lead in the presidential race has shrunk to just 2 percentage points in a new Quinnipiac university poll

NOT GOING ANYWHERE: Donald Trump's staying power is buoyed by support from white voters – and now one-third of Hispanics

DEAD HEAT: Clinton leads by 2 percentage points in a poll where the margin of error is 2.4

SHRINKING: Clinton's lead hasn't been this small in any recent poll

But Quinnipiac University pollsters warned that both presumptive nominees are hated by large numbers of the American public, and their mud-slinging is turning off voters.

'It would be difficult to imagine a less flattering from-the-gut reaction to Donald Trump and Hillary Clinton,' said Tim Malloy, assistant director of the Quinnipiac University Poll.

'This is where we are. Voters find themselves in the middle of a mean-spirited, scorched earth campaign between two candidates they don't like. And they don't think either candidate would be a good president.'

In a revised polling scenario that includes the two most prominent 'alternative' candidates, Clinton still maintains a 2-point lead over Trump, 39 to 37 per cent.

Libertarian nominee Gary Johnson and Green Party candidate Jill Stein claimed 8 and 4 per cent, respectively, but seemed to pilfer their voters in equal proportions from the two front-runners.

The Quinnipiac poll showed two ethnic trends behind the scenes of the results, with blacks favoring Hillary by an iron-clad 91-1 margin and Hispanics favoring her 50-33.

If Trump were to win the support of one-third of Hispanic voters, he would outperform both Mitt Romney in 2012 and John McCain in 2008. Those men, the last two GOP nominees, polled 27 per cent and 31 per cent, respectively, among Hispanics on Election Day.

But the national majority of white voters, the driving force behind the Trump phenomenon, are still in his corner by a 47-33 spread.

SPLIT: Americans are divided along lines of race and gender

Female voters prefer Clinton by the same 50-33 margin as Hispanics. Men choose Trump, 47-34.

Quinnipiac's pollsters found that a large majority of Americans – 61 per cent – agree that this year's presidential slug-fest 'has increased the level of hatred and prejudice in the U.S.'

Of those who said America is becoming more hate-filled and bigoted, two-thirds blamed the Trump campaign – a number that suggests most of the disaffected are Democrats.

Pollsters also found that Americans are split on key questions about which candidate is better equipped to be president – depending on which characteristics they see as most important for the job.

'American voters say 58-33 percent that Clinton is better prepared to be president than Trump; 53-33 percent that she is more intelligent and 46-37 percent that she has higher moral standards,' Quinnipiac reported.

'But voters say 45-37 percent that Trump is more honest and trustworthy and 49-43 percent that he is a stronger leader.'

America's presidential election isn't a monolithic national affair, but a collection of state-level contests. Only a handful are expected to be competitive races.

Separately from the Quinnipiac poll, a website called Ballotpedia commissioned a series of surveys from seven of thee 'battleground' states, finding that Clinton leads Trump in all of them.