I'm always happy to see someone taking on the myth that America pursued an "isolationist" foreign policy between world wars one and two. So I recommend Andrew Bacevich's latest piece for The American Conservative, which makes the point concisely:
The oft-repeated claim that in the 1920s and 1930s the United States raised the drawbridges, stuck its head in the sand, and turned its back on the world is not only misleading, but also unhelpful….Here, by way of illustrating some of those relevant facts, is a partial list of places beyond the boundaries of North America, where the United States stationed military forces during the interval between the two world wars: China, the Philippines, Guam, Hawaii, Panama, Cuba, and Puerto Rico. That's not counting the U.S. Marine occupations of Nicaragua, Haiti, and the Dominican Republic during a portion of this period. Choose whatever term you like to describe the U.S military posture during this era—incoherent comes to mind—but isolationism doesn't fill the bill.
Bacevich, by the way, is responding to a Richard North Patterson column that doesn't merely mention isolationism; it invokes "the isolationism in Europe and America which precipitated World War II." Bacevich is too kind to dwell on that phrase "isolationism in Europe," but I'll be scratching my head over it for a while. Does Patterson mean the Munich agreement? That would be a bizarre use of the word isolationist, but every other possible reference I can think of is even stranger.