The United States has long reached out to aid some of the world's most vulnerable persons, but only in the twentieth century did the practice become an important way in which both the American state and civil society staked a claim for their country as a truly global power. The term "benevolent empire" emerged in the nineteenth century as a moniker for the explosion of Protestant missionary societies that spanned the continent and lands beyond to spread the Gospel and, often, the purported benefits of American civilization. By the early twentieth century, the enterprise had begun to morph into something less overtly sacred, more diversified in its participants, committed to the modern tenets of "scientific charity" and social work, and above all, tied to the project of promoting American authority not just abroad, but at home too. The phrase "benevolent empire" may have fallen out of favor by the time armies of Americans committed themselves to unprecedentedly vast humanitarian projects during the era of the First World War, but the label still proved apt, albeit in altered ways, as the United States marched boldly through the new century. When Americans now thought of themselves as part of an imperial venture, it was likely to be at least as much about country as God. And though twentieth-century America would never quite mirror European-style territorial empires, Americans often implicitly conceptualized their country's dramatic new extensions of global power through an imperial prism that partially but significantly justified America's influence, over foreign populations by its benevolent intentions for the most vulnerable and needy among them. John Winthrop's City upon a Hill had grown big, and it refused to stay put. Book jacket.