In the autumn of 1798, Congressman Matthew Lyon of Vermont was fined $1,000 and sentenced to four months in prison. He was the first person convicted under the new Sedition Act, recently signed into law by President John Adams. It was now a crime "to write, print, utter or publish … false, scandalous and malicious writing or writings against the government of the United States." As a reckless critic of Adams and the New England political elite, Lyon made an irresistible target.

The verdict shocked many Americans. Only a few years earlier, the states had ratified the Bill of Rights, which announced in its first sentence that Congress could make no law "abridging the freedom of speech, or of the press." Now, it seemed, Congress had done exactly what the First Amendment forbade. And if a sitting representative could be imprisoned for criticizing the government, what chance did ordinary citizens have to exercise their democratic rights?

In "Liberty's First Crisis: Adams, Jefferson, and the Misfits Who Saved Free Speech," Charles Slack artfully tells the story of the rise and eventual fall of the Sedition Act. He traces its origins to the fierce presidential election of 1796 in which Adams narrowly defeated Thomas Jefferson. After the election, Jefferson's allies hurled unprecedented abuse at the new president. Adams and his supporters in Congress wished to protect themselves and, in their view, the legitimacy of the young republic from the attacks pouring out in newspapers, pamphlets, orations and private conversations.

Slack's delightful narrative focuses not on Adams and Jefferson but on the vast and eccentric group of printers, orators, politicians, amateur philosophers and visionaries who fought against the Sedition Act. We are introduced to men and women such as Philadelphia printer Benjamin Franklin Bache (grandson of Benjamin Franklin) and his wife, Margaret Markoe, who were two of the most articulate critics of the Adams administration, and to Luther Baldwin, a somewhat less articulate ferryman from New Jersey who, after a day of drinking in a pub, voiced the opinion that the president of the United States should be kicked in his backside. His subsequent arrest made him a hero.

In this period, before the Supreme Court claimed the power of voiding unconstitutional laws, the job of defeating the Sedition Act fell to these "misfits," who did much to ensure that Adams became the first one-term president and that the act was allowed to expire soon after his electoral defeat. On the last day of Adams' presidency, Matthew Lyon, who had returned from prison to serve again in Congress, sent him a blistering farewell letter. The Bill of Rights was never, Lyon wrote of the Sedition Act, "more shamefully, more barefacedly trampled on." Slack shows us how citizens such as Lyon gave the First Amendment its defining role in American politics.

Matthew Simpson is chairman of the Philosophy ­Department at Luther College in Decorah, Iowa.