07/19/2015 05:42 EDT | Updated 07/19/2016 05:59 EDT

Donald Trump's controversy-courting shtick now faces its greatest test

WASHINGTON - In one of the multiple books he's written about himself, Donald Trump lays out a secret of his success: be outrageous, be controversial, and get lots of attention.

That old formula from his business career is now undergoing an unprecedented trial in the laboratory of a U.S. presidential campaign, and the result could include more controversy than desired by even a publicity-hoarding billionaire.

Some fellow Republicans began urging Trump to apologize or drop out of the race over the weekend after he made fun of Sen. John McCain, his recent nemesis, for having been a prisoner of war.

The sudden eruption of opprobrium let loose the bubbling, weeks-old frustration among the Republican establishment that a man President Barack Obama once referred to as a carnival barker might transform their presidential contest into a circus. Any doubt over the Republican National Committee's desire for him to disappear was erased by its decision to scold him in a formal press release.

But Trump is having none of it. Not only did he refuse to apologize to McCain — he hit him even harder Sunday. He said it's the Arizona senator who should apologize, because veterans' services are so poor in the U.S.

"I will say what I want to say," Trump told ABC's Sunday morning talk show.

"And maybe that's why I'm leading in the polls. Because people are tired of hearing politicians and pollsters telling the politicians exactly what to say."

The spat with McCain began after Trump, in his presidential campaign launch speech, referred to undocumented Mexicans as rapists, criminals and drug-dealers.

The party's more moderate faction fumed that such talk, while possibly thrilling some of their grassroots primary audiences, would cause long-term damage for the party with the fast-growing Hispanic community.

McCain jumped in and accused Trump of "firing up the crazies."

That prompted an exchange at a Saturday event in Iowa where, in the span of a few seconds, Trump offered an oscillating assessment of the party's 2008 presidential nominee that ran from, "He's not a war hero," to, "He's a war hero because he was captured," to "Perhaps he's a war hero."

But the put-down that stuck out was: "I like people that weren't captured."

In his six years as a Vietcong prisoner McCain suffered two broken arms and a leg when his plane was shot down; he was bayoneted and had his shoulder crushed with a rifle butt; was frequently tortured; had his teeth broken off; and turned down an offer to be released earlier than other American POWs.

Around that time Trump was given control of his father's real-estate company. He'd gotten Vietnam deferments, for school and then because he had bone spurs in his foot.

One rival, former Texas governor Rick Perry, said Trump should apologize to McCain or drop out of the race. He was being similarly roasted on all the Sunday political talk shows.

"The remarks were so crude, ignorant, personal and completely unnecessary," said Fox News analyst Brit Hume.

"I think that reaction will be quite widespread, and will be quite damaging. He needs to apologize, and it remains to be seen if he has sense enough to do that."

Others at the Iowa event said it wasn't the remarks about McCain that caused the most grumbling. To a heavily evangelical Christian crowd, he referred to the holy communion host as "a little cracker"; used the words "damn" and "hell"; and said he never requests foregiveness from God.

In his 1987 book, "The Art of the Deal," Trump described why he craves attention — and his recipe for obtaining it.

He wrote that even the greatest product in the world is worthless if people don't notice it. For example, he said, there are lots of great singers — as good as Frank Sinatra — crooning in their garages because nobody's ever heard of them.

"You need to generate interest, and you need to create excitement," he wrote.

"The point is that if you are a little different, or a little outrageous, or if you do things that are bold or controversial, the press is going to write about you. I've always done things a little differently, I don't mind controversy."

He got lots of it Sunday.

Instead of leading with the historic, controversial Iran nuclear deal that has the potential to reshape the geopolitics of the Middle East and beyond, almost every weekly political talk show opened with Trump.