The Donald's post-debate behaviour could backfire
In August, Democratic Senator Elizabeth Warren tried to get under Donald Trump's skin by tweeting that the Republican presidential nominee "can't handle the fact that he's losing to a girl".
Trump's behaviour since the first presidential debate, judged a win for Hillary Clinton by pundits and national poll respondents, suggests Warren may have had a point.
For most of September, Trump campaigned in a more disciplined fashion. He did not get sidetracked by petty grudge matches. He stayed on message, even when addressing his supporters at televised rallies. He almost sounded presidential.
Much of that has gone out the window since his debate with Clinton.
Immediately afterwards, he loudly congratulated himself for not bringing up Bill Clinton's sexual indiscretions during the 90-minute encounter with his general election opponent.
This, along with his surrogates' post-debate talking points, was widely interpreted as a threat to bring them up during subsequent debates.
Trump has also gone on late-night Twitter rants about the media and Clinton's comments during the debate.
In recent weeks, this was an impulse he had mostly kept under control.
One of the lines of attack that seems to have rattled Trump the most is Clinton invoking former Miss Universe Alicia Machado, a Hispanic woman the GOP candidate allegedly mocked when he ran the beauty pageant, calling her "Miss Piggy" and suggesting she had a weight problem.
The day after the debate, Trump said of Machado: "She was the worst we ever had. The worst. The absolute worst. She was impossible. She was the winner, and she gained a massive amount of weight, and it was a real problem."
Machado's own past is not without controversy, but not only does the incident reinforce Trump's negatives as someone who is insensitive toward women and Hispanics. It also caused him to reignite his vendetta against Machado - similar to his criticisms of Rosie O'Donnell - in ways few Americans are likely to find presidential.
Josh Barro of 'Business Insider' made the case that Clinton's provocation was deliberate, calling it the "perfect psy op to derange Donald Trump."
Either way, both Trump's baiting of Bill Clinton and continued discussion of Machado threaten to shine a spotlight on the thrice-married businessman's own less-than-pristine sexual history.
The latest revelation has been his cameo appearance in a softcore Playboy film in 2000. Maybe Trump can succeed where other Republicans have failed in making an issue of Bill Clinton's sex life - including allegations of rape, assault and other non-consensual behaviour in addition to well documented adultery - and Hillary's role in marginalising accusers. But there's evidence dating back to the 1990s that would suggest it's risky.
In the past, voters who aren't already guaranteed to vote against the Clintons have tuned out talk about Bill's sex life and viewed Hillary more sympathetically. Unless it's a feint, Trump is playing with fire.
There is also a risk that Trump's slide in the polls since the debate will make him tune out the advisers who have finally professionalised his campaign: "I tried it your way, he might be thinking to himself. Now I'm going back to doing things my way." (© Daily Telegraph London)