When Clinton and Trump voters were asked if their vote is for their candidate or against the other, 67 percent of Clinton voters said their vote was for her while 28 percent said it was more of a vote against Trump.
Clinton now has a 48-33 lead, a huge turnaround from her narrow 42-39 advantage last month.
New polls are showing that younger voters are considering third-party candidates from the Green and Libertarian parties, which could prove to be a problem for Clinton in the race against Donald Trump. But almost 7 in 10 Democrats who back Clinton do so out of support for her.
In 2008, Barack Obama - who ultimately beat Republican John McCain by a 53 percent to 46 percent margin in the November election - did not show such a wide polling advantage over his Republican rival until late October, according to NBC/WSJ polls.
In Michigan, another Democratic-leaning Rust Belt state that Trump is trying to put in play, he trails Clinton by nine points (41% to 32%) in a survey by Detroit News and WDIV-TV. Democratic Gov. Maggie Hassan leads incumbent GOP Sen. Even illegal immigration, the issue that has energized Trump's campaign from the start and is a major concern in Florida, is named by just 5% as the "most important" issue. That lead was attributed partly to a post-convention bump.More news: Security experts: Remotes are hackable on many vehicles
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On top of that, a number of key Republicans and donors to the GOP expressed criticism towards the billionaire businessman, with some actually pledging support for Clinton because of Trump's increasingly erratic behaviour. Johnson pulls 11% support, while Stein garners 2%.
In addition, a recent national poll conducted by Fox News predict a 49-to-39 Clinton victory.
Over the past week, Trump has been mired in a public feud with the family of slain Army Capt. Humayun Khan after his father, Khizr Khan, bashed him in a speech at the Democratic National Convention. A CNN/ORC poll this week showed Clinton with a similar 9-point edge over Trump nationally. The margin of error is likely larger for subgroups, such as African-Americans, within the poll.
The Georgia poll, commissioned by the Atlanta Journal-Constitution, shows Clinton with a 44-40 lead on Trump.
Most likely Florida voters reported having negative views of the 2016 race.
The McClatchy-Marist survey reached 983 registered voters between August 1-3 and was statistically significant within 3.1 percent.