Michael D'Antonio is the author of the new book, " The Truth About Trump ." The opinions expressed in this commentary are his

(CNN) It's come to this. Donald Trump said on Tuesday that his opponent Hillary Clinton "wants to abolish, essentially abolish the Second Amendment. By the way, if she gets to pick her judges, nothing you can do, folks." Trump followed his claim, which was not supported by any source or proof, with a not-so-veiled suggestion, adding, "although the Second Amendment people, maybe there is."

For years fringe figures on the right have spoken of "Second Amendment solutions" in ways that leave little doubt they are talking about people using their guns to solve political problems. In the uproar that followed Trump's remarks, his staff said he was only referring to the voting power of gun rights supporters. However, Clinton supporters believe Trump implied a threat of violence against her. The Secret Service, which is tasked with protecting both Clinton and Trump, may have to investigate the candidate's statement. The agency recently looked into a Trump surrogate's suggestion that Clinton be executed "for treason."

No one should be mistaken about Trump's intentions. He has consistently used rhetorical sleights of hand to say outrageous things without being held responsible for them. Trump's Second Amendment statements came a day after he said he heard "many people saying" that Clinton was linked to the Iranian government's execution of a scientist who aided the United States.

After the mass shooting at Orlando's Pulse nightclub he said that "there are a lot of people that think" President Obama willfully ignores key facts about terrorism. For years he repeatedly talked about how he heard that many people thought Obama was not born in Hawaii and thus not legitimately president of the United States.

Throughout his own campaign for president, Trump has referred to unnamed sources, typically multiplied with terms like "a lot" and "many" to say outrageous things without taking responsibility for them. He has mentioned people who "think" Clinton administration aide Vince Foster, who committed suicide, was murdered and that "a lot of people are talking about" the possibility that his primary campaign rival Ted Cruz was not born in the United States.

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Every time he uses this technique, Trump gives himself an excuse in the event he is proven wrong: He wasn't saying something himself. He was merely talking about things he had heard.

This weaseling has been going on for a long time. In June 2015 Trump used his "people say" technique in the rambling address he delivered when he declared his candidacy. He noted that "people are saying, `Oh you don't like China.' I love China." Other people, according to Trump, said they "want to cut the hell out of" Social Security, but he doesn't. Still other "people" said Trump wouldn't run for president, but he was proving them wrong. (When I first met him, in 2013, Trump told me that "a lot of people" were urging him to run for president.)

It may be harmless to claim nameless supporters who say you should run for president and unidentified critics who think you hate China. But by last autumn, when Trump was a leading candidate for the GOP nomination, he was willing to take the "people are saying" trick to a new and dangerous level.

When a man stood up at a rally in Rochester, New Hampshire , to spout a bit of conspiracy theory nonsense about terrorist training camps established in the United States, Trump replied, "You know, a lot of people are saying that, and a lot of people are saying that bad things are happening out there. We're going to look at that and plenty of other things."

As he chose to inflame fears, rather than calm them, Trump demonstrated that his instincts run counter to those of Sen. John McCain. When he was running for president McCain faced a questioner who insisted then-candidate Barack Obama was an "Arab" and therefore not to be trusted. He corrected her, saying, "No ma'am." When crowds at his rallies chanted derisively about his opponent, McCain said, " We will be respectful. I admire Sen. Obama and his accomplishments. I will respect him ."

How did Trump get into the habit of making ugly statements and unsubstantiated claims? I think it began back in the 1970s when he was a budding real estate developer and discovered he wasn't going to be held responsible for things he said and did.

First he got away with deceiving the city of New York about his control of a valuable piece of property. Next came outlandish claims about how he was going to build the world's tallest skyscraper and a football stadium. Neither of these projects came to pass, but Trump was forgiven the hype because in those days, he was just a businessman with big dreams.

Photos: Donald Trump's rise President-elect Donald Trump has been in the spotlight for years. From developing real estate and producing and starring in TV shows, he became a celebrity long before winning the White House. Hide Caption 1 of 37 Photos: Donald Trump's rise Trump at age 4. He was born in 1946 to Fred and Mary Trump in New York City. His father was a real estate developer. Hide Caption 2 of 37 Photos: Donald Trump's rise Trump, left, in a family photo. He was the second-youngest of five children. Hide Caption 3 of 37 Photos: Donald Trump's rise Trump, center, stands at attention during his senior year at the New York Military Academy in 1964. Hide Caption 4 of 37 Photos: Donald Trump's rise Trump, center, wears a baseball uniform at the New York Military Academy in 1964. After he graduated from the boarding school, he went to college. He started at Fordham University before transferring and later graduating from the Wharton School, the University of Pennsylvania's business school. Hide Caption 5 of 37 Photos: Donald Trump's rise Trump stands with Alfred Eisenpreis, New York's economic development administrator, in 1976 while they look at a sketch of a new 1,400-room renovation project of the Commodore Hotel. After graduating college in 1968, Trump worked with his father on developments in Queens and Brooklyn before purchasing or building multiple properties in New York and Atlantic City, New Jersey. Those properties included Trump Tower in New York and Trump Plaza and multiple casinos in Atlantic City. Hide Caption 6 of 37 Photos: Donald Trump's rise Trump attends an event to mark the start of construction of the New York Convention Center in 1979. Hide Caption 7 of 37 Photos: Donald Trump's rise Trump wears a hard hat at the Trump Tower construction site in New York in 1980. Hide Caption 8 of 37 Photos: Donald Trump's rise Trump was married to Ivana Zelnicek Trump from 1977 to 1990, when they divorced. They had three children together: Donald Jr., Ivanka and Eric. Hide Caption 9 of 37 Photos: Donald Trump's rise The Trump family, circa 1986. Hide Caption 10 of 37 Photos: Donald Trump's rise Trump uses his personal helicopter to get around New York in 1987. Hide Caption 11 of 37 Photos: Donald Trump's rise Trump stands in the atrium of the Trump Tower. Hide Caption 12 of 37 Photos: Donald Trump's rise Trump attends the opening of his new Atlantic City casino, the Taj Mahal, in 1989. Hide Caption 13 of 37 Photos: Donald Trump's rise Trump signs his second book, "Trump: Surviving at the Top," in 1990. Trump has published at least 16 other books, including "The Art of the Deal" and "The America We Deserve." Hide Caption 14 of 37 Photos: Donald Trump's rise Trump and singer Michael Jackson pose for a photo before traveling to visit Ryan White, a young child with AIDS, in 1990. Hide Caption 15 of 37 Photos: Donald Trump's rise Trump dips his second wife, Marla Maples, after the couple married in a private ceremony in New York in December 1993. The couple divorced in 1999 and had one daughter together, Tiffany. Hide Caption 16 of 37 Photos: Donald Trump's rise Trump putts a golf ball in his New York office in 1998. Hide Caption 17 of 37 Photos: Donald Trump's rise An advertisement for the television show "The Apprentice" hangs at Trump Tower in 2004. The show launched in January of that year. In January 2008, the show returned as "Celebrity Apprentice." Hide Caption 18 of 37 Photos: Donald Trump's rise A 12-inch talking Trump doll is on display at a toy store in New York in September 2004. Hide Caption 19 of 37 Photos: Donald Trump's rise Trump attends a news conference in 2005 that announced the establishment of Trump University. From 2005 until it closed in 2010, Trump University had about 10,000 people sign up for a program that promised success in real estate. Three separate lawsuits -- two class-action suits filed in California and one filed by New York's attorney general -- argued that the program was mired in fraud and deception. Trump's camp rejected the suits' claims as "baseless." And Trump has charged that the New York case against him is politically motivated. Hide Caption 20 of 37 Photos: Donald Trump's rise Trump attends the U.S. Open tennis tournament with his third wife, Melania Knauss-Trump, and their son, Barron, in 2006. Trump and Knauss married in 2005. Hide Caption 21 of 37 Photos: Donald Trump's rise Trump wrestles with "Stone Cold" Steve Austin at WrestleMania in 2007. Trump has close ties with the WWE and its CEO, Vince McMahon. Hide Caption 22 of 37 Photos: Donald Trump's rise For "The Apprentice," Trump was honored with a star on the Hollywood Walk of Fame in January 2007. Hide Caption 23 of 37 Photos: Donald Trump's rise Trump appears on the set of "The Celebrity Apprentice" with two of his children -- Donald Jr. and Ivanka -- in 2009. Hide Caption 24 of 37 Photos: Donald Trump's rise Trump poses with Miss Universe contestants in 2011. Trump had been executive producer of the Miss Universe, Miss USA and Miss Teen USA pageants since 1996. Hide Caption 25 of 37 Photos: Donald Trump's rise In 2012, Trump announces his endorsement of Republican presidential candidate Mitt Romney. Hide Caption 26 of 37 Photos: Donald Trump's rise Trump speaks in Sarasota, Florida, after accepting the Statesman of the Year Award at the Sarasota GOP dinner in August 2012. It was shortly before the Republican National Convention in nearby Tampa. Hide Caption 27 of 37 Photos: Donald Trump's rise Trump appears on stage with singer Nick Jonas and television personality Giuliana Rancic during the 2013 Miss USA pageant. Hide Caption 28 of 37 Photos: Donald Trump's rise In June 2015, during a speech from Trump Tower, Trump announced that he was running for President. He said he would give up "The Apprentice" to run. Hide Caption 29 of 37 Photos: Donald Trump's rise Trump -- flanked by U.S. Sens. Marco Rubio, left, and Ted Cruz -- speaks during a CNN debate in Miami on March 10. Trump dominated the GOP primaries and emerged as the presumptive nominee in May. Hide Caption 30 of 37 Photos: Donald Trump's rise The Trump family poses for a photo in New York in April. Hide Caption 31 of 37 Photos: Donald Trump's rise Trump speaks during a campaign event in Evansville, Indiana, on April 28. After Trump won the Indiana primary, his last two competitors dropped out of the GOP race. Hide Caption 32 of 37 Photos: Donald Trump's rise Trump delivers a speech at the Republican National Convention in July, accepting the party's nomination for President. "I have had a truly great life in business," he said. "But now, my sole and exclusive mission is to go to work for our country -- to go to work for you. It's time to deliver a victory for the American people." Hide Caption 33 of 37 Photos: Donald Trump's rise Trump faces Democratic nominee Hillary Clinton in the first presidential debate, which took place in Hempstead, New York, in September. Hide Caption 34 of 37 Photos: Donald Trump's rise Trump apologizes in a video, posted to his Twitter account in October, for vulgar and sexually aggressive remarks he made a decade ago regarding women. "I said it, I was wrong and I apologize," Trump said, referring to lewd comments he made during a previously unaired taping of "Access Hollywood." Multiple Republican leaders rescinded their endorsements of Trump after the footage was released. Hide Caption 35 of 37 Photos: Donald Trump's rise Trump walks on stage with his family after he was declared the election winner on November 9. "Ours was not a campaign, but rather, an incredible and great movement," he told his supporters in New York. Hide Caption 36 of 37 Photos: Donald Trump's rise Trump is joined by his family as he is sworn in as President on January 20. Hide Caption 37 of 37

As the Republican Party's presidential candidate Trump occupies a position that comes with a greater expectation of accuracy and honesty. This would seem doubly true of someone who regularly criticizes the press as "slime" and "scum" and "disgusting, dishonest human beings" The one exception Trump has offered to this assessment of the media is the National Enquirer, which was the source he credited during a discussion about a supposed relationship between Ted Cruz's father and the assassination of John F. Kennedy.

"What I was doing was referring to a picture reported and in a magazine, and I think they didn't deny it," said Trump "I don't think anybody denied it." In truth Cruz had already condemned the Enquirer's story as false, adding that a photo published with it did not show his father, as the paper claimed. Trump then doubled down on his statement saying, "You can't knock the National Enquirer."

As he praised the Enquirer, Trump may have been the first national politician to ever embrace a supermarket tabloid as a paragon of truth. More recently he has claimed to be acting like a journalist himself, "reporting" news to crowds at his rallies. When he erroneously claimed that he has seen a video of a plane delivering cash from America after a hostage release, he told a crowd, "I don't think you've heard this anywhere but here." He was correct in saying that no one else had reported that, and in fact Trump withdrew the claim soon after.

But even if Trump later drops a claim, it's likely some of his supporters will continue believing the initial falsehood. This is how Trump's game is played. Someone "hears" something and repeats it so someone else can "hear" it and soon enough, Vince Foster's suicide becomes a murder and President Obama is foreign-born Muslim. (If you need help understanding how dangerous Obama is, just refer to Trump's insinuation, made in June, that "there's something going on" between the president and Islamic extremists who plot and carry out terror attacks .) Voters can be excused if they feel they can't trust anyone to tell them the truth. If they listen to Trump, they certainly can't expect to get the facts from the press.

When combined with his loose sourcing for so many of his claims. the Trump record is so bad that it raises genuine concern about his ability to process information and speak plainly about things. This helps to explain why 50 foreign policy experts who have served Republican presidents have signed a letter saying they cannot support Trump . They wrote that Trump, "is unable or unwilling to separate truth from falsehood."

The open letter from the foreign policy experts represents one way to check Trump's methods and counteract them. Another has emerged in social media. The popular hashtag on twitter invites people to share their thoughts under the heading, ManyPeopleAreSaying. Among the entries so far are "@RealDonaldTrump is a secret Muslim" and "many people are saying I deserve a raise."