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.”