The electoral map has gone from bad to worse for Donald Trump, as a series of new state-level polls show him falling further behind Hillary Clinton.

The Democratic nominee's position has improved so significantly that the Presidential Poll Tracker now awards her 273 electoral college votes from "safe" states alone, putting her over the 270-vote mark needed to win the White House.

Despite claims from Trump that the polls are "getting close," a string of polls conducted by Marist College for NBC News and the Wall Street Journal suggests the opposite, with states thought to be battlegrounds showing Clinton opening up a wide lead over the Republican presidential nominee.

In Virginia , Clinton led with 43 per cent to 31 per cent for Trump, 12 per cent for Gary Johnson (Libertarian), and five per cent for Jill Stein (Green). That represents a drop of five points among decided voters since the pollster's last survey in mid-July.

, Clinton led with 43 per cent to 31 per cent for Trump, 12 per cent for Gary Johnson (Libertarian), and five per cent for Jill Stein (Green). That represents a drop of five points among decided voters since the pollster's last survey in mid-July. In Colorado , Clinton was ahead with 41 per cent to 29 per cent for Trump, 15 per cent for Johnson, and six per cent for Stein. Trump was down five points here as well.

, Clinton was ahead with 41 per cent to 29 per cent for Trump, 15 per cent for Johnson, and six per cent for Stein. Trump was down five points here as well. In North Carolina , a state won by Mitt Romney by two points in 2012, Clinton led with 45 per cent to 36 per cent for Trump, nine per cent for Johnson, and two per cent for Stein, a decrease of two points for Trump.

, a state won by Mitt Romney by two points in 2012, Clinton led with 45 per cent to 36 per cent for Trump, nine per cent for Johnson, and two per cent for Stein, a decrease of two points for Trump. And in Florida, Clinton had 41 per cent to 36 per cent for Trump, nine per cent for Johnson, and four per cent for Stein. Both Clinton and Trump dropped two points since July.

While Clinton now has a more comfortable lead in North Carolina and Florida in the Poll Tracker, the poll in Colorado has flipped the state into the "safe" category. This means that if the election were held today, Clinton would have a 95 per cent chance of winning the state.

Polls have also recently nudged New Hampshire, Wisconsin, Pennsylvania, and Virginia into safe territory for the Democrats.

Democratic presidential candidate Hillary Clinton has widened her edge over Donald Trump in the decisive electoral college. (Andrew Harnik/Associated Press)

Two post-convention polls in New Hampshire have given Clinton a lead of 12 to 16 points among decided voters, while four polls in Virginia have estimated her edge to be either 10 or 15 points. And a new survey conducted in Wisconsin by the Marquette Law School put her ahead by 14 points.

These are not margins easily overcome, even with some 88 days to go before the vote. If Trump were to mount a comeback by November, he would be the first presidential candidate to do so from such a deficit.

A 'Southern Strategy' for the Democrats?

The last Democrat to win South Carolina was Jimmy Carter in 1976. Mitt Romney won the state four years ago by 10.5 points for the Republicans.

A new poll by Public Policy Polling put Trump ahead in the state by merely two points, 41 to 39 per cent.

In neighbouring Georgia, four post-convention polls have varied between a four point lead for Trump to a four point lead for Clinton among decided voters.

These two states are ones that did not start the campaign as battlegrounds, but have suddenly become states that could flip to the Democrats.

But they aren't electorally important states. If Clinton were to win them, she would likely already be well above the 270 mark in the electoral college vote, and these states would just pad her margin of victory. But that these states are on the bubble shows just how disastrously this election could go for the Republicans.

Trump still has time to turn things around — he has managed many unlikely feats in his short political career. But he will need to change his erratic and undisciplined campaigning style to pull it off. His track record suggests that may not be realistic.

The Presidential Poll Tracker includes all published mainstream surveys, a list of which can be found here. The polls are weighted by sample size and date, as well as the reliability of each pollster as rated by FiveThirtyEight.com. The electoral college is projected by applying the same weighting standards to state-level polls and combining this with a uniform swing model, based on how the current national polling average compares with the 2012 presidential election. Surveys included in the model vary in terms of sample size and methodology and have not been individually verified by the CBC. A full methodological explanation can be found here.