In 1897, a half-dozen great powers claimed sovereignty over nearly half the world’s land and souls, and these empires were expanding. The British Empire alone had grown by fifty million souls and two million square miles since 1891. The eminent naval strategist Alfred T. Mahan feared that the United States was dangerously secluded, in comparison, and sidelined in the global land rush underway. He also worried that the Atlantic Ocean no longer adequately protected the U.S. against European powers in an age of steamships. Like his fellow Republicans Theodore Roosevelt and Massachusetts Senator Henry Cabot Lodge, Mahan influentially advocated U.S. expansionism. He envisioned the United States ruling acquired lands as colonies. Their residents were as politically unfit for rule as children, criminals, women, and African Americans, he believed. But the Constitution presented a problem. Nearly three decades had passed since the last U.S. annexation. As Mahan complained, “any project of extending the sphere of the United States, by annexation or otherwise, is met by the constitutional lion in the path.”