Those of us who said Trump's refusal at the debate to acknowledge he would accept the election results would cost him any possible chance he may have still had to win this election were correct.
Fifty-nine percent of likely voters, moreover, reject Trump’s suggestion that the election is rigged in Clinton’s favor, and more, 65 percent, disapprove of his refusal to say whether he’d accept a Clinton victory as legitimate. Most strongly disapprove, a relatively rare result.
Clinton Vaults to a Double-Digit Lead
From the link, the most important section down at the bottom.
Methodology
"a random national sample of 874 likely voters"
"Results have a margin of sampling error of 3.5 points, including the design effect. Partisan divisions are 36-27-31 percent, Democrats-Republicans-independents."
So a small sample of people, 874 and a 9% oversampling of Democrats, 36% Democrats, 27% Republicans is again of course going to result in Hillary leading another poll.
There isn't a 9% over sampling of Democrats. Turn out among Democrats in a presidential election is typically higher than turn out among Republicans. It might be slightly over sampled, but in the last two presidential elections turn out among Democrats was roughly 7% higher than Republicans.
Furthermore, 874 people is not a small sample. It's very typical of most polling and more than enough for a scientific poll.
"It might be slightly over sampled, but in the last two presidential elections turn out among Democrats was roughly 7% higher than Republicans."
This election you have is very different than your previous elections.
What you have are the Trump voters, who include not only Republicans, but also Conservative Independents and Constitutional Conservatives etc. The Trump voters think that if Hillary wins then this is going to be the last election, no more elections, a consolidation of power from the Hillary side.
Then you have the section, who might not like Donald Trump, however they're concerned about the Supreme Court situation, that in the next four years, three Judges might have to be replaced, and lifetime positions, so the Second Amendment at huge risk, possibly also the First Amendment and maybe others.
So these things combined, suggest that the Trump voters and what we'll refer to as the Anti-Hillary voters, in significantly higher numbers are going to vote, which is why I think that previous elections, where the Democratic turnout was a little higher cannot be included this time.
There is no precedent or parallel to this election, at least in contemporary times, perhaps if I read there might be one pre-American Civil War or post-American Civil War or something, I'm not sure I'll have to read some things.