Bookmakers have slashed odds on Donald Trump being replaced before the presidential election

Betting company Ladbrokes has slashed the odds of Donald Trump being replaced as the Republican candidate, from 16/1 to 6/1, following a bad week of campaigning.

Trump is still taking a lot of criticism for his insinuation that Ghazala Khan - the mother of an American Muslim soldier killed on duty - was being quiet while her husband spoke at the DNC because she was not allowed to talk.

Even other Republicans took issue with these remarks against the grieving mother of a soldier, with Sen. Lindsey Graham telling ABC that "there used to be some things that were sacred in American politics - that you don't do - like criticizing the parents of a fallen soldier even if they criticize you."

Trump's behaviour seems to have really turned off the electorate, with a Fox News poll published on Wednesday giving Democratic rival Hillary Clinton a big 10-point lead. An even more recent McClatchy-Marist poll gives Clinton a massive 15-point lead, which puts her in potential landslide win territory.

Trump does not seem to like his own party

Another turn-off for the GOP has been Trump's apparent reluctance to endorse other Republicans - even when his own running mate Mike Pence has. Earlier in the week Trump refused to confirm his support for House Speaker Paul Ryan, as well as senators John McCain and Kelly Ayotte.

But Trump seems to be aware that getting his own party back on-side is probably a good idea, calling Ryan 'a good guy' in a speech on Thursday and discouraging the crowd from booing at the very mention of his name.

So could Trump actually be replaced? Republican party rules state that (emphasis ours):

"The Republican National Committee is hereby authorized and empowered to fill any and all vacancies which may occur by reason of death, declination, or otherwise of the Republican candidate for President of the United States or the Republican candidate for Vice President of the United States."

Nathaniel Persily, Stanford law professor, told the Daily Beast the Republican National Committee could replace Trump with a vote of No Confidence and a re-nominate a person with a majority vote - not necessarily Pence, the VP candidate.

However, Persily said that with the bureaucratic nightmare of the state ballot and electoral college that would follow any such vote, Republicans are very unlikely to bother unless Trump chooses to drop out.