American strategy in the Asia Pacific over the past two centuries has been marked by strong and often contradictory impulses. On the one hand, the western Pacific has served as a fertile ground for Christian missionaries, an alluring destination for American commercial enterprises, and eventually a critical launchpad for U.S. global power projection. Yet on the other hand, American policymakers at times have subordinated Asian strategy to European-based interests, or have found themselves embroiled in area conflicts that have hampered efforts to extend U.S. regional hegemony. Furthermore, leading countries in the Asia-Pacific region at times have challenged U.S. economic and military objectives, and the assertion of “Asian values” in recent years has undermined efforts to expand Western political and cultural norms. The United States’s professed “pivot to Asia” has opened a new chapter in a centuries-long relationship, one that will determine the geopolitical fault lines of the 21st century.