An entrepreneur who revolutionized the automobile business decides he now needs to change how the world thinks, so he buys a media property to use as a megaphone. His rants validate many people’s worst impulses while also encouraging enemies of democracy around the world.

This sounds like Elon Musk and his social media site X in 2025, but it was also Henry Ford and his paper, The Dearborn Independent, in the 1920s. Ford, the inventor of the Model T, bought a suburban weekly and remade it to push his antisemitic views. The Dearborn Independent published a long-running series called “The International Jew,” which blamed Jews for the world’s ills, and publicized “The Protocols of the Elders of Zion,” a hoax document. The Nazis gave Ford a medal.

Ford was perhaps the most blatant example in a long tradition of moguls who bought media platforms and then used them to promote odious views. These tycoons often used the latest in technology to reach the widest audience, whether it was high-speed newspaper presses or, in Ford’s case, his network of car dealerships.

Drive off in your new Model T and there would be The Dearborn Independent on the seat. Newspapers at the time were local businesses. With the dealerships, The Dearborn Independent became one of the highest-circulated papers in the country, printing more than 750,000 copies of each issue at its peak.

The biggest difference between Ford and other media titans like Rupert Murdoch was that the latter generally promoted their views by hiring like-minded editors and anchors. The Dearborn Independent announced on its cover that it was the “Ford International Weekly,” and it included a full-page editorial signed by Ford.

Mr. Musk’s actions signal a return to Ford’s personal approach. The Tesla and SpaceX billionaire has enthusiastically posted, reposted and endorsed incorrect or inflammatory claims on X that Social Security is fraudulent, that the Democrats are importing immigrants to win elections and that the federal judges who are ruling against the Trump administration should be impeached.

There are plenty of precedents for what Mr. Musk is doing with X. But he has taken the process to a level unimaginable even a short time ago. The site says he has 220 million followers, an assertion impossible to verify. Even if it is only a fraction of that number, X has been optimized to blast its owner’s posts as widely as possible. People see them and hear about them.

Mr. Musk’s $44 billion purchase of what was then Twitter in 2022 at first seemed to be a mistake, even to him. Then it was perceived as a billionaire’s toy. In last year’s election, it became a weapon. He used his political views to form an alliance with Donald J. Trump, which he then leveraged to put himself into the government expressly to shut down as much of it as possible.

The repercussions are still unfolding. But for Mr. Musk, it was a clear victory. In the name of government efficiency, agencies fired regulators who were in a position to oversee his empire. Mr. Musk now has a much freer hand with his cars and rockets. (An X spokesman did not provide a comment.)

“This is like nothing we’ve ever seen,” said Rick Perlstein, author of a four-volume chronicle of modern American conservatism. Noting Mr. Musk’s frequent use of memes and images, the historian added: “It’s the politics of the nervous system, not the higher functions of the brain. There’s no argument, just fear mongering.”

Moguls in the United States and Britain have owned media with the purpose of exerting influence since the creation of the modern newspaper in the late 19th century. During World War I, Viscount Northcliffe of Britain controlled roughly 40 percent of the morning circulation and 45 percent of the evening circulation there. His properties included The Daily Mail, read by the working class, and The Times, read by the elites.

The viscount, whose name was Alfred Harmsworth, played a crucial role in deposing Prime Minister Herbert Asquith in December 1916. Winston Churchill wrote that the press baron “aspired to exercise a commanding influence on events.” Viscount Northcliffe’s influence on the war was so great that the Germans sent warships to assassinate him in 1917, shelling his seaside home.

In the United States, the control of the media was often more of a local phenomenon. In West Texas in the early 1960s, the ultraconservative Whittenburg family owned The Amarillo Daily News, the NBC television station and the dominant radio station. There were few competing voices.

“If you feed people a far-right media diet, you’ll end up with a population almost exclusively on the far right,” said Jeff Roche, a historian who wrote “The Conservative Frontier,” a forthcoming study of the politics of the region. “Amarillo became the most right-wing city in America.”

“Media ownership and political influence have gone hand in hand since the earliest days of the newspaper industry,” said Simon Potter, a professor of modern history at the University of Bristol who studies mass media. “For just as long, people have worried about this intimate relationship between the media and politics — does it really serve the public interest?”

Behind that question is another: Does their megaphone really give them power, or is it shouting into a void? An American forerunner of Mr. Musk — William Randolph Hearst — provides an answer. Hearst, the owner of the upstart New York Journal, sent correspondents to Cuba in 1897 to cover a war with Spain. His interests were less humanitarian than promotional. He was in a circulation war.

One version of how that story played out showed Hearst as an all-powerful media magnate:

The Journal correspondents discovered there was no war. “Everything is quiet,” Frederic Remington, the paper’s illustrator, cabled Hearst. “There will be no war.” They wanted to leave.

Hearst replied: “Please remain. You furnish the pictures and I’ll furnish the war.” He then agitated in his papers for the war that President William McKinley in short order began. It liberated Cuba and acquired for the United States prized parts of the Spanish empire.

The story was first published in a book by a colleague of Hearst’s named James Creelman and later immortalized in Orson Welles’s “Citizen Kane.” It has been thoroughly debunked over the years. There was no evidence that Hearst ever said he would supply a war. The correspondents found plenty to illustrate. But the anecdote persisted because it showed a mogul so powerful that he could make wars out of nothing.

When Hearst tried to move on from his wartime endeavors to advance his own political career, he stumbled. He secured a seat in the House of Representatives in 1902, but bids to become the mayor of New York faltered twice. He lost a 1906 campaign for New York governor, too.

David Nasaw, who wrote “The Chief: The Life of William Randolph Hearst,” thinks Mr. Musk’s use of X to rally supporters is as illusory as Hearst’s supposed creation of a war.

“I haven’t seen anywhere that Twitter gets out the MAGA vote,” he said.

Hearst, in Mr. Nasaw’s view, reflected the sentiments of his readers rather than leading them. But the historian agreed that something new was going on with Mr. Musk. Hearst, Ford, even Viscount Northcliffe and the other British press lords before World War II, all had something in common that ultimately limited them.

“They were outside the room, screaming,” Mr. Nasaw said. “Twitter was important for Musk but only to get him inside the room, into the government. He’s unique in being both inside and outside with no constraints on his behavior. There’s never been anything quite like that.”

Tesla sales are plunging. Hearst and Ford could have warned Mr. Musk: Courting controversy with hateful views is bad for your reputation and usually bad for your business, too.

Ford was sued for libel over The Dearborn Independent and became the subject of boycotts. He closed the paper in 1927, although he did not repent his views. A stain lingered.

Hearst went up against President Franklin D. Roosevelt in the 1930s, putting his anti-Roosevelt screeds on the front page of his papers. As the editorials became increasingly abusive, readers had to choose: Whom are we going to support, the president or the publisher?

“They chose Roosevelt,” Mr. Nasaw said. “Which meant Hearst eventually destroyed himself and his newspapers.”