Story highlights Clinton leads Trump, 50% to 42%

Clinton maintains her edge with third party candidates included

Washington (CNN) Hillary Clinton leads Donald Trump by 8 percentage points -- doubling her lead from a month ago in the latest ABC News/Washington Post poll.

Clinton leads Trump, 50% to 42%, in a head-to-head race, the survey of registered voters found. With Libertarian Party nominee Gary Johnson and Green Party nominee Jill Stein added to the race, Clinton maintains her 8-point lead, 45% to Trump's 37%, Johnson's 8% and Stein's 4%.

The poll found huge gaps in voters' take on the two candidates' attributes. Asked whether the candidates have the right personality and temperament to be president, 61% said Clinton does, while 31% said Trump does. Just 33% said Trump understands international matters, while 72% said Clinton does.

Trustworthiness is a problem for both candidates: Only 38% view Clinton as honest and trustworthy, and just 34% say Trump is honest and trustworthy.

The survey shows the damage of Trump's criticism of the Khan family -- the parents of a US soldier killed in combat who blasted Trump at the Democratic National Convention.

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