When it comes to sport, bookmakers sometimes pay out early if a team is running away with it. There's a risk to this, of course, because there is always an outside chance that the tables will be turned at the last moment.

But the bookies gamble that the publicity from such a stunt makes it worth the risk.

With this year's presidential election, however, it's looking more and more as though they will be able to pay out early with minimal risk. Donald Trump's behaviour is getting stranger by the day. He's on a one-man self-destruct mission, and it looks as though he has thrown in the towel.

Sure, he's still chucking bombs wherever he can – at Hillary Clinton, at his Republican colleagues, at the media, at the women who have accused him of sexual misconduct. But he's long given up on any pretence of appealing to the mainstream – those voters who he simply has to win over he wants to beat Clinton – and instead is going full-on with his anger and conspiracy theories.

If, as some suggest, all this is simply a warm-up act for his real ambition of launching a TV station, he's doing well. He might be alienating large swathes of the population but there's a sizeable minority who adore him, and as far as they are concerned he can do no wrong.

A quick look at the comments on some of the lunatic websites that support Trump show just what a hero he has become to a great many people. Forget the fact that this is a man who has chucked money at politicians for years – he has, somehow, managed to create a myth that he is this great outsider, riding in to shake up the establishment.

And his supporters love him for it – and will turn on anyone who disagrees with them. A single Tweet pointing out any character flaw Trump might have is met with vitriolic responses. Any Republican who expresses discomfort with Trump's behaviour is subjected to horrendous abuse. Death threats are not uncommon.

And Trump is feeding this anger and these conspiracy theories. The election is rigged, he says. The media is in cahoots with Clinton, apparently. His Democratic candidate was on drugs during the last debate, he alleges. And so on.

Perhaps the weirdest thing Trump has done recently – and it's a heck of a high bar to clear – is to accuse Clinton of enabling her husband's sexual misconduct. He has hurled all kinds of accusation at Bill Clinton in the hope of making mud stick on her. Yet he must have known that this was one area where he himself was vulnerable.

So having slammed Hillary Clinton for apparently mounting a campaign to discredit her husband's accusers, he has now gone on a campaign to discredit his own accusers. By raising the Clintons' history, all he has done is magnify his own misdemeanours.

We're now approaching the third and final televised debate. Expect plenty more mud to be thrown from both sides, with Trump leading the way. But early voting is already well under way, and with Clinton's lead in the polls growing, it's probably too late for Trump to produce a game-changer.

Depending on which poll you trust, Clinton is ahead by anything between 4pc and 11pc, More crucially, she is leading in most of the important battleground states. Even Utah, which is a solidly Republican state, is showing signs that it might be in play for the Democrats. That's how much trouble Trump is in.

A large event could yet change things, but at this stage it looks as though the Republican nominee is going to be solidly beaten on November 8. Keep an eye open for the first bookie to pay out.