The trial that gave birth to press freedom: 290 years on

On 5 August 1735, a jury in New York took just 10 minutes to deliver a verdict that would echo down the centuries. John Peter Zenger, a printer and publisher of The New York Weekly Journal, was acquitted of seditious libel after printing criticisms of the colonial governor. The jurors knew he had broken the law as it then stood, but they acquitted him anyway. It was an act of jury nullification that, in the words of Founding Father Gouverneur Morris, became "the germ of American freedom, the morning star of that liberty which subsequently revolutionized America".

The case matters because it established the principle that truth could be a defence against libel, a radical idea at a time when English common law held that the greater the truth, the greater the libel. That principle now underpins press freedom across the Western world, enshrined in the First Amendment to the US Constitution and, eventually, in British law through the Libel Acts of 1792 and 1843. Without Zenger's acquittal, the modern understanding of a free press might look very different.

A printer caught in a political storm

Zenger was a German-born immigrant who arrived in New York as part of the Palatinate Migration of 1710. He learned the printing trade under William Bradford, the city's first printer, and later became his partner on The New York Gazette, a newspaper that was studiously loyal to the colonial government. But when Brigadier General William Cosby arrived as governor in 1732, his high-handed and self-interested style quickly alienated leading figures in the colony.

Cosby clashed with Rip van Dam, a merchant and president of the Governor's Council, and with Lewis Morris, the chief justice of the New York Supreme Court. Morris was removed from office for ruling against the governor. The opposition, known as the Popular Party, needed a voice. The only other printer in the city was Zenger, and on 5 November 1733 he published the first issue of The New York Weekly Journal, funded by Van Dam, Morris and others. It carried anonymous articles that tore into Cosby's administration.

Eight months in prison, then a landmark trial

Cosby responded by ordering copies of the Journal burned on Wall Street. Two grand juries refused to indict Zenger, so the governor issued a proclamation condemning the paper's "scandalous, virulent, false and seditious reflections". The new chief justice, James De Lancey, issued a bench warrant, and Zenger was arrested for seditious libel in November 1734. He spent eight months in jail, continuing to write for the Journal with articles headed "From my Prison".

At trial on 5 August 1735, Zenger was represented by Andrew Hamilton, a former attorney general of Pennsylvania and one of the best advocates in the colonies. Hamilton admitted that Zenger had printed the offending material, but argued that the criticisms were true and that every free-born subject had the right to publish truth. The prosecuting attorney, Richard Bradley, countered that truth was irrelevant: the law said that true statements could be libellous. Hamilton appealed directly to the jury, telling them that the case was not about a poor printer or New York alone, but about "the cause of liberty" for every freeman under British government in America.

The jury withdrew and returned within 10 minutes. The foreman, Thomas Hunt, announced the verdict: not guilty. The courtroom erupted in cheers, and Zenger was released the following day.

A slow revolution in law and opinion

The Zenger verdict did not immediately change the law, but it changed how people thought about censorship and criticism of authority. In the United States, the First Amendment, ratified in 1791, prohibited Congress from abridging freedom of speech or of the press. The Sedition Act of 1798, while criminalising seditious libel, for the first time allowed truth as a defence in federal law.

In Britain, the shift was slower but unmistakable. The Libel Act 1792 gave juries the power to decide what constituted a libel, rather than leaving that to judges alone. The Libel Act 1843 established the defence of truth provided it was published for the public benefit. The common law offence of seditious libel was finally abolished by the Coroners and Justice Act 2009.

Today, the idea that the government cannot suppress facts because they are inconvenient is taken for granted in most democracies. But it was not always so. When John Peter Zenger stood in the Supreme Court of New York on that August day in 1735, the freedom of the press took a great stride forward. The jury's 10-minute deliberation changed the world.