WASHINGTON — Whatever else might be said about the curious lawsuits filed last week by former President Donald J. Trump, in which he accused three big tech companies of violating his First Amendment rights by denying him access to their platforms, it is fitting that he sued in Florida.

The state has long been on the cutting edge, and on the losing end, of efforts to force private companies to publish political messages to which they object.

Almost 50 years ago, the Supreme Court struck down a Florida law that would have allowed politicians a “right to reply” to newspaper articles critical of them. And late last month, a federal judge in Florida blocked a new state law that would have imposed large fines on some tech companies (but not those that own theme parks in the state, like Disney) that “willfully deplatform a candidate for office.”

Together, the two decisions, one from the Nixon era and the other issued on June 30, demonstrate that the lawsuits Mr. Trump filed in Miami on Wednesday against Facebook, Twitter and YouTube face steep odds. The First Amendment applies to government censorship and not private activities, courts have said, and it protects publishers’ editorial judgments, including ones that decline to give politicians a forum.

The case that gave rise to the 1974 Supreme Court decision was brought by Pat L. Tornillo, who was displeased by colorful editorials in The Miami Herald opposing his candidacy for the Florida House of Representatives. The newspaper said Mr. Tornillo, a labor union official, had engaged in “shakedown statesmanship.”

Mr. Tornillo invoked a Florida law that required newspapers to give candidates they criticized free space for a reply “in as conspicuous a place and in the same kind of type.” The newspaper refused, lost in the state’s highest court and appealed to the U.S. Supreme Court.

Mr. Tornillo and his supporters said, in Chief Justice Warren E. Burger’s summary, that “a communications revolution” and “the specter of a ‘wired’ nation” justified the law, as did “the vast accumulations of unreviewable power in the modern media empires.”

All of that may be so, Chief Justice Burger wrote for a unanimous court. But the First Amendment, he wrote, does not permit the government to usurp the role of editors in deciding what ought to be published.

“A responsible press is an undoubtedly desirable goal,” he wrote, “but press responsibility is not mandated by the Constitution, and like many other virtues it cannot be legislated.”

Justice Byron R. White, who was often hostile to the news media, wrote in a concurring opinion that an unregulated and unruly press is better than the alternative of government control.

“Of course, the press is not always accurate, or even responsible, and may not present full and fair debate on important public issues,” he wrote. “But the balance struck by the First Amendment with respect to the press is that society must take the risk that occasionally debate on vital matters will not be comprehensive and that all viewpoints may not be expressed.”

Less than two weeks ago, Judge Robert L. Hinkle of the Federal District Court in Tallahassee blocked another Florida law, this one enacted in May and animated by some of the same ideas rejected by the Supreme Court in 1974. The law would impose fines on some social media platforms for exercising editorial judgments in declining to amplify the views of politicians who ran afoul of their standards.

In a statement issued when he signed the bill, Gov. Ron DeSantis, a Republican, said the point of the law was to promote conservative viewpoints. “If Big Tech censors enforce rules inconsistently, to discriminate in favor of the dominant Silicon Valley ideology, they will now be held accountable,” he said.

Judge Hinkle cited the Tornillo decision but wrote that there are significant differences between newspapers and platforms like Facebook and Twitter.

“Newspapers, unlike social media providers,” he wrote, “create or select all their content, including op-eds and letters to the editor,” he wrote. By contrast, he wrote, “something well north of 99 percent of the content that makes it onto a social media site never gets reviewed further.”

But the new law, Judge Hinkle wrote, was aimed at “ideologically sensitive cases,” ones in which the platforms used discretion much as newspapers do.

“Those are the very cases on which the platforms are most likely to exercise editorial judgment,” he wrote. “Indeed, the targets of the statutes at issue are the editorial judgments themselves.”

Perhaps the oddest part of the law was its exclusion of social media providers under common ownership with large theme parks. That discrimination, an apparent favor to powerful local businesses, was reason enough to subject the law to the most demanding form of constitutional scrutiny, Judge Hinkle wrote.

Mr. DeSantis has said the state will appeal, and there is at least one member of the Supreme Court who seems open to considering whether new technologies require new rules. In April, Justice Clarence Thomas issued a concurring opinion when the court turned down a case on whether Mr. Trump had violated the First Amendment by blocking people from his Twitter account, saying it was moot.

Justice Thomas used the occasion to muse on a larger question, one pertinent to both the Florida law and Mr. Trump’s lawsuits.

“Today’s digital platforms provide avenues for historically unprecedented amounts of speech, including speech by government actors,” he wrote. “Also unprecedented, however, is the concentrated control of so much speech in the hands of a few private parties. We will soon have no choice but to address how our legal doctrines apply to highly concentrated, privately owned information infrastructure such as digital platforms.”