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

In the late 19th century, the main US foreign policy was
imperialistic.  The US was trying to expand its global reach, taking such places as
Hawaii, Guam and the Philippines.

I would say that the main
"old" factor was a desire for more wealth and power.  The US was pursuing these in a
different way than it previously had because it was now looking to colonize other
countries rather than to expand its own country.  But it was still the same
idea.

I see two relatively "new" factors.  First was the
idea of "white man's burden."  The US had had Manifest Destiny before, but not this idea
of civilizing other people.  Second was competition with other imperial powers.  The US
had not previously been interested in building an empire outside North
America.