BRISTOL — Guess what happened to the antiwar protesters who threw anonymous pamphlets from a rooftop, urging people to go on strike because the president had sent troops to another country?

They were sentenced to 20 years in prison and the nation’s top court upheld their conviction on sedition charges.

From the vantage point of modern America, that outcome might seem stunning. “A piece of political criticism, criticizing a president’s policy — can you imagine anything that’s more central to the idea of what you are allowed to say in this country?” two-time Pulitzer Prize winner Anthony Lewis asked during a speech last week at the Roger Williams University School of Law.

But it happened in the United States, and it happened not all that long ago. The U.S. Supreme Court issued its ruling in Abrams v. United States in 1919, and the dissent, by Justice Oliver Wendell Holmes Jr., marked the first time a Supreme Court justice had written an opinion “treating freedom of speech as a fundamental value,” Lewis said.

Holmes’ dissent came 128 years after the adoption of the First Amendment — which says, “Congress shall make no law … abridging the freedom of speech, or of the press” — and it came a dozen years before someone seeking First Amendment protection for expression actually won a Supreme Court case, Lewis said.

“Now that’s quite a remarkable fact,” Lewis said, “because I think most of us regard the First Amendment expression clauses as something that came down from the top of Mount Sinai and there it was and that was it: We had the freedom of speech and press and the courts enforced it and we all lived happily ever after. Not so.”

Lewis, a former New York Times columnist and reporter who won a Pulitzer Prize for his coverage of the Supreme Court, is the author of a new book, Freedom for the Thought We Hate: A Biography of the First Amendment. Many say they were inspired to become lawyers by his 1964 book, Gideon’s Trumpet, which tells the story of the landmark Supreme Court case that gave indigent criminal defendants the right to a lawyer.

Lewis spoke at Rhode Island’s only law school on Wednesday as part of the school’s “Supreme Semester,” which is giving students a chance to meet three Supreme Court justices — Chief Justice John G. Roberts Jr., who visited the state on Feb. 12; Justice Antonin Scalia, who will visit the law school on April 7; and Justice Samuel Alito Jr., whom students will visit on April 14 in Washington, D.C.

Lewis said many of the Supreme Court’s early First Amendment cases dealt with opinions. “But what about facts?” he asked.

“Opinions are cheap — facts are dear,” he said, paraphrasing former Manchester Guardian editor C.P. Scott. “Can you protect publication of facts? That was the issue in the Pentagon Papers case in 1971.”

He recounted how the Nixon administration tried to stop The New York Times from publishing excerpts from a secret official history of the origins of the Vietnam War, and how the Supreme Court ruled that the injunctions were unconstitutional prior restraint.

In his concurring opinion, Justice Hugo Black said, “Paramount among the responsibilities of a free press is the duty to prevent any part of the government from deceiving the people and sending them off to distant lands to die of foreign fevers and foreign shot and shell.”

After reading that line, Lewis said, “It’s not altogether distant from where we are today, is it?”

Lewis said he disagrees with some of the First Amendment rulings the Supreme Court has made in more recent years. But overall, he said, “the court has been very expansive in its views of freedom of speech. The important thing is that the concept of freedom of expression now has support across the spectrum on the court and in the country — right to left.”

Lewis emphasized that our modern understanding of the First Amendment comes from the rulings that judges have made since 1931. The First Amendment contains “sweeping words” but, he said, “They have no content without judicial elaboration.”

In a New York Times review of the book, author and law professor Jeffrey Rosen said, “There is a competing, decidedly less heroic account of First Amendment history, which holds that judges have always tended to reflect the public’s prejudices about unpopular speakers, and that most advances for free speech have been initiated not by judges, as Lewis argues, but by the political system.”

When the Journal asked him about that critique, Lewis said, “I give the public ample credit. Judges and the public have acted together. Judicial opinions, like those stirring opinions of Justice Holmes, arouse public sentiment, and the public then wasn’t so scared of radical speech and was more favorable to letting people talk, and the judges were encouraged by the public attitude to do more.”

The Journal also asked Lewis about the government’s efforts in recent years to put reporters behind bars or to threaten them with prison for failing to divulge sources.

“Journalists have to rely on anonymous sources,” Lewis said. “It’s especially true that they must when a whistleblower is exposing wrongdoing in the government because ordinarily a person in the government who is telling you some horrible thing that’s been done can’t say, ‘Oh, sure, use my name,’ because then he’ll be fired.”

But, Lewis said, “There are times when other values outweigh the journalistic claim.”

For example, he cited the case of Wen Ho Lee, a scientist at the Los Alamos National Laboratory who was described by the press as an atomic spy. He was charged with 59 felony counts, but the government dropped all but one count — a charge that he mishandled information retroactively classified as “secret.” Lee sued the government for violation of his privacy in the press leaks, and he subpoenaed reporters, seeking their sources. The reporters refused to divulge their sources and were held in contempt until five news organizations agreed to pay Lee a total of $750,000.

“I asked myself: Would we want to live in a country in which a man’s life could be destroyed with no recourse?” Lewis said. “Sometimes there are other interests, other values that come in.”

efitzpat@projo.com