The meteoric rise of the United States in the nineteenth century has long attracted the attention of historians and political scientists. Scholars have charted in meticulous detail the upstart nation’s transformation from a motley conglomeration of former British colonies into a transcontinental empire with, after the colonialist outburst of 1898, global reach. Richard W. Maass’s The Picky Eagle swims against this tide, focusing not on the conventional story of incremental expansion but instead on the many instances in which the United States left on the table opportunities to annex more territory. The central question of this study appears in the book’s first sentence: “Why did the United States stop annexing territory?” (p. 1).

To answer this question, Maass takes the reader on a whistle-stop tour of the many annexation attempts that failed in the nineteenth century, including attempted land grabs in territories in Canada, Mexico, the Caribbean, and beyond. The breadth of this study—both chronological and geographical—is one of its biggest strengths, not least in how Maass considers the (mostly successful) overland continental expansion alongside the unsuccessful attempts to annex islands, transit routes, and territories outside of what