The Supreme Court this June expanded First Amendment protections to cover public employees who don't want the state extracting union dues, voters who seek to wear political clothing or paraphernalia at the polls, and some businesses that chafe at being told by the government that they must display certain information. This has been, The Volokh Conspiracy's Jonathan H. Adler concluded, "the most speech-protective Supreme Court in our nation's history."

The citizenry, meanwhile, was moving in the opposite direction. In a memo leaked in June, staffers at the American Civil Liberties Union (ACLU) agonized that the organization's fabled commitment to the First Amendment might have a "harmful impact on the equality and justice work to which we are also committed." All summer long, rightists and leftists took turns trying to get their political opponents fired from their jobs and banished from social media platforms over speech deemed intolerable. Even on the Supreme Court, Justice Elena Kagan warned that her conservative colleagues were "weaponizing the First Amendment."

A gap that wide—and widening by the day—between the constitutional parameters of free speech and the cultural support for the stuff is not tenable in the long term. That is, if you take to heart the main argument of Barry Friedman's 2009 book The Will of the People, which is that the Supreme Court, rather than hewing doggedly to principle, is in fact sensitive to public opinion, ratifying post facto where the culture has already gone.

If today's mores produce tomorrow's First Amendment jurisprudence, we might be in for a rough patch ahead, particularly considering the retirement of Justice Anthony Kennedy, whom Adler describes as "the most speech-protective justice" on the Court. But actually, we don't have to wait to see whether the cultural turn against free speech will filter into law and the enforcement thereof. It's already happening.

The most ominous recent example is the Allow States and Victims to Fight Online Sex Trafficking Act, which was passed overwhelmingly by Congress (388–25 in the House, 97–2 in the Senate) and then signed into law by President Donald Trump in April, even though it holds web publishers retroactively liable for illegal transactions conducted between their users. The law was opposed on First Amendment grounds by the ACLU, the Electronic Frontier Foundation, and such civil libertarians as Sen. Rand Paul (R–Ky.) and Sen. Ron Wyden (D–Ore.), the latter of whom warned that there could be "an enormous chilling effect on speech in America."

But even on issues like antitrust enforcement and the long-dead, ill-advised Fairness Doctrine, Republican politicians and commentators are abandoning positions they've held for decades. It's not just President Trump making threats on Twitter, either.

When the local-TV chain Sinclair Broadcast Group sought to purchase Tribune Co.'s television stations, former Republican House Majority Leader Tom DeLay objected that "the spectrum Sinclair utilizes to broadcast is limited," then added in a Politico essay the conservative-sounding twist that the merger "would set a terrible precedent by opening the door for ABC, CBS, and NBC to also buy many more TV stations. At that point, nothing can stop liberal Northeast corporate executives from telling homes in the heartland what to think." The deal was abandoned in August after the Federal Communications Commission (FCC) raised procedural objections to some of Sinclair's pre-merger activities.

The Department of Justice's less successful attempt to block a merger between AT&T and Time Warner has also inspired from the Justice Department the kind of vigorous antitrust argument "that hasn't been made by any Republican, conservative administration ever—not even by Obama," as Vanderbilt Law School's Rebecca Haw Allensworth told The Washington Post.

Politicians respond to incentives created by voters, and right now voters want speech suppressed. Sens. Bernie Sanders (I–Vt.), Elizabeth Warren (D–Mass.), and nine of their colleagues have asked the FCC to consider revoking Sinclair's license altogether, based on content concerns. Sen. Ted Cruz (R–Texas) recently said that breaking up big tech companies in the name of free speech is an issue he is "looking at seriously."

Libertarians have expended much energy over the years making the important distinction between First Amendment issues and the broader category of "free speech." But it's also crucial to recognize that, in the famous Andrew Breitbart phrase, politics is downstream from culture. The culture of free speech has been deteriorating for long enough that politics, sadly and predictably, is catching up.