Trump joins luminaries like Steve Forbes, Ross Perot, and Herman Cain in the roster of businesspeople who’ve tried to go from the C-Suite to the Oval Office. So, what can he learn from those who came before him?

Put simply, the message is, “don’t be like them.” Because they all lost, and lost spectacularly.

“Very little has worked when businesspeople have tried to translate into the political realm,” said Jeane Zaino, a political science professor at New York University.

Some of the biggest flameouts from recent years: Pizza magnate Herman Cain led the polls briefly in late 2011, but a sexual harassment scandal combined with a few embarrassing gaffes related to foreign policy led him to suspend his campaign before primary season even started.

Publisher Steve Forbes sought the Republican nomination in 1996, but won just two primaries, coming in third behind Pat Buchanan and eventual nominee Bob Dole.

Ross Perot, a tech entrepreneur, ran as an independent in both 1992 and 1996. In 1992, he actually won a remarkable 19 million votes, but didn’t manage to win a single state or electoral vote.

And if you want to go way back, corporate lawyer Wendell Wilkie won the Republican nomination in 1940, before a formal primary system was in place, but he was trounced in the general election by sitting president Franklin Roosevelt.

Businesspeople with enough clout to run for president tend to have already achieved significant success and public recognition—with his many buildings and his reality show, Trump certainly qualifies. All of that success can lead to the misguided belief that whatever recipe led to their rise in business will somehow work in politics. “I think candidates who feel they can translate that easily are stunned, if not shocked” about the world of difference between what is required of a businessman versus a politician, Zaino said.

For one thing, their relationship with the media will change. As a businessperson, the media is mostly interested in what makes your company work — how you operate, what your strategy is, etc. Once you’re running for office, the media wants to know about your position on every policy, they want to know about your personal life, and they want to know about your family—and you have to take it, or else you look bad.

Zaino brings up a moment in 2012 when Cain, after being asked an annoying question by a reporter, looked at an adviser and remarked that the campaign would have teach this journalist how to behave. In a country that desires openness from its politicians even more than it dislikes the press, that was a bad move.

Given that Trump has a history of testy relationships with the media — see his epic Twitter meltdown after a somewhat unflattering BuzzFeed article last year — this could be a real problem as the bloodhounds of the political media corps are let loose on Candidate Trump.

The biggest hurdle for businesspeople trying to become politicians, though, is the fact that communicating a business plan with your employees is extremely different from communicating a plan for a country to voters. No matter how much we may say otherwise, a nation is not a business. And the tactics that work when you want to sell your rank-and-file at Company X that your plan will make everyone rich will not fly when you need to sell a Middle America voter that your plan will bring peace and prosperity to everyone.

Herman Cain became a laughingstock for his “9-9-9” plan, because it was the kind of buzzword laden, details-sparse strategy that looks good on the cover of an annual report to shareholders but not so hot when you have to explain in a debate how you plan on implementing it.

Now, some business candidates can make this work. Zaino points to Ross Perot. “Perot, I think, did a masterful job,” she said. “His whiteboard, speaking to people in a very common-sense fashion.” Trump, however, is known for bluster and extravagance, not folksy conversation. Zaino isn’t sure he has the charm or the message to follow Perot’s lead.

To be sure, Trump is not your typical businessperson candidate. He’s a celebrity and a reality show star. But if he actually wants to make a real run at this, he’ll have to learn that those two things does not a politician make.