These two Parisian vignettes at the beginning and end of America’s Civil War illustrate much of what this book is about. The smug satisfaction of aristocratic governing classes who thought they were witnessing the demise of the democratic experiment was answered four years later by a resurgence of hope and defiant spirit among its adherents everywhere.

While the war was being fought on the battlefields of Bull Run, Antietam, and Gettysburg, another contest was waged overseas. The Confederacy sought international recognition and alliances to secure independence, and the Union was determined not to let that happen. “No battle, not Gettysburg, not the Wilderness,” one historian claimed, “was more important than the contest waged in the diplomatic arena and the forum of public opinion.” The history of Civil War diplomacy—that is, the formal negotiations among governments and the strategies surrounding them—has been told and told well. This book turns to the less familiar forum of public opinion, which was filled with clamorous debate for four years. It took place in print (in newspapers, pamphlets, and books) as well as oratory (in meeting halls, pubs, lodges, union halls, and parliaments). Wherever free speech was stifled, as it was in France, the debate continued over private dinner tables and at cafés. Whatever one’s views, there was general agreement that the American question mattered greatly to the world and to the future.

The term public diplomacy did not come into common usage until World War I, but America’s Civil War witnessed what were arguably the first deliberate, sustained, state-sponsored programs aimed at influencing the public mind abroad. Diplomats for the North and South understood the enormous power the press had gained, thanks to vast improvements in print technology and the expansion of literacy, which made cheap publications and mass-audience journalism possible. They also grasped the key role that journalists, intellectuals, reformers, dissident political leaders, and other opinion leaders had in influencing popular sentiment. Not since Benjamin Franklin’s residence there, US diplomat Henry Sanford wrote to Secretary of State William Seward from Paris in August 1861, had there been such an occasion for attention to cultivating public favor abroad. “We ought to spend money freely in the great centers in forming public opinion.”

The Union and Confederacy each hired special agents, who usually operated under cover of some kind. They were typically veteran journalists and political operators whose job it was, as one of them deftly put it, to give “a right direction to public sentiment” and correct “erroneous” reports that favored the other side. Some bribed editors and hired journalists, while others published their own pamphlets, books, and even newspapers. Few were above planting rumors or circulating damaging stories, and some of what they produced can only be described as propaganda and misinformation. But that was only part of the story of what was more often a sophisticated appeal to ideology and values.