Donald Trump’s tragic flaw by Geoff Colvin @FortuneMagazine August 14, 2015, 2:15 PM EDT E-mail Tweet Facebook Linkedin Share icons Is Donald Trump campaigning his way into business trouble? NBC, apparently not content with having cut all ties to Trump in June after his comments about Mexican immigrants, fired him again on Thursday when NBC Entertainment chairman Bob Greenblatt said Trump would “absolutely not” return as host of Celebrity Apprentice. Friday morning’s WSJ features an unflattering front-page investigation of Trump’s involvement with a marketing firm—scrutiny he wouldn’t be getting if he weren’t running for president. Those developments by themselves aren’t the problem; neither, alone, is particularly damaging to Trump. To see the real danger, remember that Trump made his fortune with an innovative business model based on personal fame. For 40 years, he has courted the media. A New York Times real estate reporter from the 1970s recalled recently that Trump “was one of those who always returned a phone call.” In 1976, an adoring Times profile observed that “He is tall, lean and blond, with dazzling white teeth, and he looks ever so much like Robert Redford. He rides around town in a chauffeured silver Cadillac with his initials, DJT, on the plates. He dates slinky fashion models, belongs to the most elegant clubs and, at only 30 years of age, estimates that he is worth ‘more than $200 million.’” All that’s changed is that his net worth has increased, and he isn’t quite so lean. As a self-created celebrity, Trump started putting his name on buildings, launching a new concept: branded high-end real estate. It worked. Trump buildings mostly did well. He even began licensing his name to other developers for buildings he didn’t own. So long as he kept himself in the public eye, the machine kept spinning. That’s why many people assumed Trump is running for president simply as another way to keep people hearing and saying his name. And maybe that’s correct. In my few chats with him over the years, I’ve found him to be thoroughly self-aware, knowing just what he’s doing, understanding that many people find him obnoxious. He’s fine with that. It all keeps the machine going. What’s new is that, as a presidential candidate egged on by thousands of cheering supporters, he’s saying things that damage the brand. Slandering immigrants, demeaning John McCain, insulting women – such statements can’t be brushed aside, and they live forever on YouTube. NBC isn’t the only organization to have severed relationships with Trump; so have Macy’s, ESPN, and Nascar. Two high-profile chefs have backed out of deals to open restaurants in new Trump properties. It’s easy to imagine that, after all these years, living in a Trump building could suddenly flip from being prestigious to being totally uncool. Trump is now at the apogee of his fame, but the process of getting there could damage his vaunted wealth. He may be doing something no leader should ever do: letting adulation wreck his judgment. Sign up for Power Sheet, Fortune’s daily morning newsletter on leaders and leadership.