What factors, old and new, shaped American foreign policy in the late nineteenth century? How were they interrelated?

In some
respects, there was nothing all that new about American foreign policy in the late 19th and
early 20th centuries. As an increasingly wealthy, powerful country, the United States closely
followed the historical example of Ancient Rome and Great Britain in expanding its reach across
the globe. Despite a persistent thread of isolationist sentiment in American foreign policy,
complete disengagement with the outside world has never been a live option for the United States
at any time in its history.

In the late 19th century, it became clear that
the United States would need to become more...