The Introduction sets out the central puzzle that the book seeks to solve. Descriptively, it asks whether primaries have transformed in the twenty-first century by using a series of case studies to illustrate the central descriptive argument of change. It then frames the importance of the second half of the book, justifying the focus on elite partisan positioning and ideological change in relation to recent primary elections as a (potential) mechanism. It then clarifies the data collection process and sources used. Finally, it focuses on partisan differences between the Republican and Democratic parties before providing an outline of the book’s structure.

Part II of the book shifts in focus from primary transformation to party transformation. This chapter tests whether primaries can change parties under the most likely conditions: Republican factional primaries in the Tea Party era. Using a difference-in-differences design, this chapter shows that in this most visible case, pressure from the reactionary Republican faction in primary elections served to reorient the party rightwards. It therefore demonstrates that, under the right circumstances, primaries can contribute to partisan polarization in Congress.

The concluding chapter quickly surveys the arc of impeachment history through the two acquittals of Donald Trump and considers whether impeachment remains a useful tool against presidential overreach and what the two acquittals of Trump suggest about the health of the American political project.

Shakespeare and George Peele’s Titus Andronicus (1591–94) stages both the proliferating texts and the religious violence of the early 1590s. These years saw a spate of sectarian libels from persecuted Puritans and Catholics alike. In Titus, the marginalized Andronici likewise launch ephemeral scraps of writing into the sky, texts that join appeals for redress with violent threats. These libels bear an especially close resemblance to those scattered in the streets by the Puritan extremist William Hacket and his accomplices in 1591. But the echoes are also cross-confessional, indicating a broader interest in the “manner” of religiopolitical speech. The play folds its topical allegory into a Tacitean-humanist history of political communication: the rise of the emperor, Saturninus, brings about the end of public oratory. Their speech silenced, the Andronici unleash a flurry of texts that takes the Tacitean story of rhetorical decline into its early modern future. By yoking libels not just to the pursuit of justice but also to factionalism and violence, Titus takes a hard look at the viral and virulent media of the late Elizabethan public sphere.

Vendetta was a commonly used term in early modern Italy and widely viewed in as legitimate, contributing to Italy’s very high homicide rates. But vendetta has received surprisingly little attention from historians. Vendetta was not opposed to the state or the law, because it was closely associated with justice. The process of getting even did not require the spilling of blood: an injury could be satisfied in bloodless ways and medieval statutes progressively sought to deny or restrict self-help. The elaboration of more punitive courts institutionalised the system of compensation for an injury. Vendetta was a process of conflict resolution in which the state, church and community brought significant pressure to bear on the parties to renounce enmity and seek peace. This became much more difficult after 1500. The Italian Wars not only unleashed mass violence and regime change on a scale not experienced in the late Middle Ages but also led to the collapse of traditional political loyalties. The violence unleased by civil war changed the nature of faction: factional identities were henceforth forged in blood.

The Sultanate drew upon concepts of martial skill, valor and aggression attributed to the Mongol Imperium and its unprecedented conquests. While idealizing these traits, Mamluk Sultans exploited them to thwart Mongol expansion into their territories. They welcomed renegades from Mongol armies (Wafidiyya) to mimic their prowess while limiting their aggression. Mamluk cadets were imported initially from the Qipjaq Steppe in Central Asia, subsequently from Circassia in the Caucasus, with numerous other regions represented. They were instructed in Arabic, Turkish and Islam prior to being trained in arms. The Mamluk military hierarchy consisted of elite Mamluks imported as cadets in the Sultan’s service, Mamluks of senior officers, soldiers of former rulers restive over their loss of status, and descendants of 1st-generation Mamluks who served as infantry and assimilated into Arabic civil society (awlad al-nas). Advancement through the military hierarchy was marked by endemic factional rivalry in which conspiracy was expected not repudiated. Whether conspiracy enhanced the Sultanate’s military prowess or destabilized its governance remains a debated issue.

An Estimate of the Manners and Principles of the Times (2 vols., 1757–8) by John Brown (1715–66) has rarely been studied in depth by intellectual historians, incongruent to its own initial popularity at publication. The Estimatewas written in a declinist voice, following hard on the heels of Britain’s defeat by France at the Battle of Minorca in 1756. Brown was convinced that Britain’s initial bad fortunes in war against France were related to a general decline in manners and principles, exemplified by the spirit of party. Even more understudied is Brown’s final contribution on the subject: his Thoughts on Civil Liberty: On Licentiousness and Faction, published in 1765, one year before he committed suicide. In this work, Brown tried to do what many political writers, including the principal ones discussed in this book, had held to be impossible: to demonstrate how a free state could exist without the internal conflict exemplified by party.

This chapter is devoted to several brief sections and sets the stage for what follows by dealing with some of the key elements of context and background for the remainder of the book. These include: ancient politics and political thought in Greece and especially Rome; the distinction (and non-distinction) between party and faction; Jacobitism; Scotland, Wales, Ireland, and the nature of the eighteenth-century British fiscal-military state; and sociability and partisanship. It concludes by highlighting that the most common way to discuss and write about political parties in the eighteenth century was in political, historical, and constitutional terms.

This chapter describes grassroots activism and the FA’s peculiar organizational structure in which 7,000 grassroots activists have a significant autonomous voice in the FA decision-making bodies. Grassroots activists’ participation in the FA occurs in Base Committees (the movement) and in the different FA factions (the coalition), two different avenues of engagement with the FA. In the former, there is no direct control of factions, leaders, or party elites because Base Committees are not involved in candidate selection. The chapter provides a thick description of the party´s structure and shows the relevance of activism in the FA and its interaction with leaders and factions in party life.

What impact did the Scottish Enlightenment have on the American founding? Given the variegated, feisty composition of the Scottish Enlightenment, this chapter resists the idea that that movement had any single, unequivocal effect on America. It instead surveys the rich array of ways in which Scottish thought found its way into America and then examines a series of interactions between particular Scottish thinkers and particular American activists. What was Frances Hutcheson’s influence on Thomas Jefferson? Did David Hume or Adam Smith have a greater influence on Madison? What lessons did various American educational leaders take away from Thomas Reid’s response to David Hume? By looking in detail at these three cases, the chapter attempts to convey the flavour, as well as the content, of the reception of Scottish philosophy in America.