WASHINGTON -- Anyone professing shock over the symphony of personal slurs delivered by Donald Trump clearly wasn't paying attention to him before he became a presidential candidate.

For more than a quarter-century, he's chronicled in exhaustive detail his passion for put-downs. He's written, granted interviews and tweeted repeatedly about the value of vengeance.

He even titled an entire book chapter, "Revenge."

His current political rivals John McCain, Rick Perry, Lindsey Graham, Carly Fiorina, and Fox News personality Megyn Kelly, will recognize the modus operandi spelled out in his pre-politics musings.

His value system doesn't abide turning the other cheek. Rather, it responds to every ounce of criticism with a multi-tonne Mack Truck of ad-hominem degradation.

"I tell people, 'Get even!' This is not your typical advice, get even, but this is real-life advice," he wrote in "Think BIG And Kick Ass In Business And Life."

"If you don't get even, you are just a schmuck!"

He begins the chapter by describing his well-documented feud with actress Rosie O'Donnell, and how he'd silenced her criticism of him with insults -- crude ones referring to her weight and physical appearance, and a cruel suggestion for how she might cure her depression: stop looking in mirrors.

Some of those insults resurfaced last week in the Republican debate, when Fox moderators read some out. That prompted Trump to attack the moderators, and he made an apparent menstruation joke about Kelly.

The outrage was instantaneous.

Trump was disinvited from an event -- and he responded by insulting the event host, calling him a "loser" in a press release. Some rival candidates said he'd finally gone too far -- so he countered by suggesting one of them, Fiorina, the race's only woman, could induce a headache with the sound of her voice.

Once again, pundits began writing his political obituary. They did the same thing when he attacked McCain's war record and later when he publicly released Graham's cellphone number.

One fumed that politics is the art of adding support, not of antagonizing everybody in sight: "I think that reaction will be quite widespread, and will be quite damaging," Fox's Brit Hume predicted after the attack on McCain.

He's been wrong so far. Trump's still in first place in the Republican field. But Hume might ultimately be proven right, since poll numbers suggest the growth potential of Trump's campaign is limited by the even larger number of voters who dislike him.

In the meantime, don't expect him to change.

His aversion to forgiveness is deeply ingrained. The words he used in a 1990 interview with Playboy magazine were a near-verbatim replica of what he's told political talk shows in recent days.

"When somebody tries to sucker-punch me, when they're after (me), I push back a hell of a lot harder than I was pushed in the first place," he told the magazine 25 years ago. "If somebody tries to push me around, he's going to pay a price."

He also shared a personal anecdote in that book chapter on revenge, published eight years ago.

Trump wrote about a superstar athlete, a basketball player he did not identify who's supposedly a household name. He said the athlete told him he'd been ripped off by an agent.

Trump says he was ready to help with a lawsuit, and planned to get a particularly vicious lawyer to help the athlete take revenge. But, apparently, that athlete was the type to let it go.

And in Trump's world there's no room for tolerating slights.

"He said, 'I can't do it!"' Trump wrote, with incredulity.

"I said, 'That's okay, but never, ever call me again, because you are a schmuck!' I have not spoken to the guy since. He calls me once in a while, but I don't ever talk to him, because he is a loser.

"You have to show people you can't be pushed around."