The greatest enemy of liberty is fear. When people feel comfortable and well protected, they are naturally expansive and tolerant of one another's opinions and rights. When they feel threatened, their tolerance shrinks. By 1798, the euphoria surrounding the American Revolution, the sense of a common purpose and a common enemy, was gone. Everyone agreed that the new nation founded amid high hopes and noble ideas was in danger of collapse. The one thing they could not agree on was who to blame.

The Federalists, who dominated most of New England as well as both houses of Congress, the John Adams presidency, and the Supreme Court, viewed themselves as the protectors of family, faith, education, and country. Though the term "federalism" refers only to the system of shared powers between individual states and a centralized government forged by the Constitution, under the leadership of men such as Alexander Hamilton, principal author of the Federalist Papers, it had come to imply a decisive tipping of the scales in the direction of centralized power. Hamilton and other Federalists believed in a strong national military to protect the fledgling country from foreign invaders, a centralized bank to stabilize and grow the economy, and a government with the muscle to tax and to direct the destiny of the nation. They had little faith in the intelligence or morals of average men. As such, they believed in liberty, yes, but liberty as informed and guided by a natural aristocracy consisting of themselves.

Yet everywhere they turned, they saw their orderly utopia of English-descended freemen under siege, rapidly devolving into something more volatile and chaotic. For this, Federalists blamed an unofficial, disparate but growing collection of citizens referring to themselves as Republicans, or Democrats, or Democratic-Republicans, or Jeffersonian Democrats. In the interest of simplicity, they'll be referred to henceforth as Republicans, but with no inference of a connection or lineage to the modern party of the same name. Indeed, the word "party," now so firmly rooted in our political language that one might assume party structure was written into the Constitution, was an epithet in 1798. Men in power used "party" interchangeably with "faction" and "interest" to designate outliers, troublemakers, and enemies of good government.

In their innocence, the founding generation assumed that a government chosen by the people would represent all the people. Federalists, who had controlled most of the national government from its inception, never considered themselves to be a political party; to oppose the Federalists was to oppose the very idea of America. In his farewell address at the end of his second term in 1796, President George Washington, the great unifier, had warned against "the baneful effects of the Spirit of Party," and "the alternate domination of one faction over another, sharpened by the spirit of revenge natural to party dissention."

Yet to those calling themselves Republicans, Federalist efforts to unify the country were beginning to look a lot like what they had just fought a war to overturn. Everything from Washington's fancy carriage to John Adams's thin-skinned reaction to criticism to Alexander Hamilton's emerging master plan for a muscular national bureaucracy had the whiff of privilege and elitism, if not incipient monarchism. Federalists, to Republican minds, were "aristocrats" and "royalists" bent on consolidating power and replicating English class divisions on American soil. Like the Federalists, Republicans believed their American utopia to be under siege, but their greatest fears surrounded the very measures that Federalists saw as the country's salvation. The idea of a powerful national military (a "standing army" in the parlance of the day) raised the fresh specter of British troops forcibly quartered in the homes of colonists. A federal government capable of taxing at will elicited memories of usurious taxes imposed by a distant monarch.

Against this background of internal divisions, Americans were panicked over a possible imminent invasion by a great European power. The trouble was they could not agree on which European power, England or France, would do the invading. Fueled by hatred for the English monarchy, Republicans felt a spiritual connection with the French, who had not only aided the American Revolution but also launched a revolution of their own.

Federalists, for their part, had watched in growing horror as the French Revolution degenerated into a procession of rolling heads and bloodlust. They saw in that revolution a chilling forecast of what the United States could expect from its own population without strong, principled leadership from the elite. Indeed, they saw themselves as the last barrier against Republican-driven chaos. Radicals, revolutionaries, and malcontents from around Europe were streaming onto American soil and stirring things up.

Federalists mistrusted foreigners in general and immigrants in particular, especially of the poor and non-English variety. Alarmed by the numbers of Germans, French, and Irish pouring each year into their cities and towns, Federalist politicians had proposed a ban on anyone born outside the United States holding government office, along with a twenty-dollar naturalization fee for immigrants — no small amount at a time when an American farmhand might get by on six to twelve dollars a month. In July 1797, Congressman Harrison Gray Otis of Massachusetts sounded the alarm on immigration in what became known as the "Wild Irish" speech, warning that while he had nothing against "honest and industrious" immigrants, the country could not afford to "invite hordes of wild Irishmen": "The mass of vicious and disorganizing characters who could not live peaceably at home, and who, after unfurling the standard of rebellion in their own countries, might come hither to revolutionize ours." Everything that Otis and his fellow Federalists feared, hated, and scorned could be summed up in three words: Congressman Matthew Lyon.

A native of Ireland, Lyon had schemed and brawled his way from indentured servitude to the upper layers of business and politics in his adopted country. Everything about his life was outsized: his ambition, his intelligence, his enemies, and his flaws. He never let an insult pass without returning it twofold. Put simply, Matthew Lyon couldn't keep his mouth shut. It was this quality above all others that resulted in his greatest, albeit unintentional, contribution to the American experiment. His belligerence in the face of Federalist power would help push the United States into a constitutional crisis, forcing a generation that had soured from idealism to bitterness to confront a few epic questions. Would they live up to the words they themselves had forged, upholding freedom of expression as the highest form of liberty? Did they truly mean what they had said, that Congress shall make no law abridging free speech, or freedom of the press?

Records of his early life in Ireland are murky, so it's impossible to say for sure what prompted Lyon to leave his native...