The phrase "Banned in Boston" has its origins in the early 1900s. Boston may have trailed New York in most ways, but it led the nation in practicing censorship based on moral grounds. The driving force behind the city's puritanical purges was the Watch and Ward Society, founded in 1878 to "watch and ward off evildoers."

According to the Globe, during the heyday of the Watch and Ward, "the Boston Public Library kept books the society considered objectionable in a locked room, the Museum of Fine Arts kept part of its Asian collection behind closed doors, and the label 'banned in Boston' became a selling point for salacious books from New York to San Francisco." The members of the Watch and Ward Society encountered little resistance — until they targeted H.L. Mencken.

Known as "the Bard of Baltimore," where he was born in 1880, Mencken rejected his Methodist upbringing and made it a habit, in the words of one biographer, "to speak out forcefully, pungently, and satirically against the follies of religion." He was particularly critical of religious fundamentalists, whom he blamed for attempting to use the power of government to enforce their moral views. The passage of Prohibition in 1920 enraged him, as he believed deeply that people should pursue their happiness with as little government interference as possible. Censorship also angered him. In 1922 Mencken declared, "I am, in brief, a libertarian of the most extreme variety, and know of no human right that is one-tenth as valuable as the simple right to utter what seems (at the moment) to be the truth."

A skillful reporter, Mencken earned a national reputation covering the Scopes "Monkey" trial in Tennessee for the Baltimore Sun. He skewered attorney William Jennings Bryan for proposing that teaching evolution should be a crime and depicted him as a religious "fanatic, rid of sense and devoid of conscience." He championed Clarence Darrow as a defender of free speech and the Bill of Rights.

One of several magazines he edited was the American Mercury, which frequently included pieces critical of established social conventions and authorities. He loved to lampoon the self-righteous enforcers of morality in Boston. He famously defined Puritanism as "the haunting fear that someone, somewhere may be happy."

Mencken relished the chance to take on the Watch and Ward Society; in doing so, he was striking a blow to the heart of Boston's Protestant elite. The Society was founded in 1878 to fight corruption in business and politics; in 1906 it shifted its attention to defending conventional morals and became a "citizen's vigilance" group protecting Boston from vice.

City officials did not question the Watch and Ward Society's right to define what was and was not obscene. It reviewed books, plays, and other forms of artistic expression, looking for moral corruption. If the Society deemed an item obscene, it would notify local booksellers and news dealers. Under a gentleman's agreement with city police, the vice squad would arrest anyone who continued selling the offending work. A person who purchased a banned book risked prosecution for violating the state's obscenity laws.

The April 1926 issue of the American Mercury was irresistible to the Watch and Ward Society. It contained an ad for a book deemed obscene and an essay proposing a "New View of Sex" as purely "a pastime for leisure hours." But it was "Hatrack," a short story by Herbert Asbury that generated the most notice. Asbury (later the author of The Gangs of New York) wrote a purportedly true account of a prostitute from his hometown in Missouri who regularly sought forgiveness at the local Methodist church. The congregation shunned her and, unsaved, she continued her life of sin, meeting her Catholic customers in the Protestant cemetery and her Protestant customers in the Catholic graveyard.

When the Watch and Ward Society immediately banned the issue as obscene, Mencken boarded a train for Boston. Once in the city, he orchestrated a meeting with John Chase, the Society's director, at the "Brimstone Corner" on Boston Common. With police, press, and a rowdy crowd of students on hand, Mencken offered Chase a copy of the magazine. Chase gave him a half-dollar piece (which Mencken bit for effect). Within minutes, the Boston vice squad placed H.L. Mencken under arrest.

In court, the judge found that the magazine was not obscene and acquitted Mencken on all charges. Mencken then sued the Watch and Ward Society for illegal restraint of trade. Again he was successful. A federal judge ruled that it was the responsibility of prosecutors, not private citizens, to censor literature.

H.L. Mencken was not quite done with lawsuits. Just a few days after his victory in Boston, the Solicitor of the U.S. Post Office declared that, despite the judge's ruling, American Mercury was obscene and therefore sending it through the mails was a federal offense. Mencken responded by suing the U.S. Post Office. A month later, the courts dismissed the case on a technicality since the magazine had already been mailed and delivered. Mencken was disappointed; he had hoped his suit would become a landmark free-speech case.

H.L. Mencken died in 1956. By then the Watch and Ward Society had changed its name to New England Citizens Crime Commission and shifted its focus to gambling. The organization gained national attention in 1962 when it helped CBS News expose Boston police involvement in betting. A Miami newspaper reported, "Not since the British imposed a tax on tea have Bostonians been so aroused."