Question

Why did the United States shift from expanding internally toward foreign expansion in the late 1800s and early 1900s?

Answer 1

I don't have the full info, but at that time, it was due to the idea of Manifest Destiny which was expanding to the end of the continent. You know know the U.S looked like in the beginning right?
Also, because of the race of imperialism, the U.S was afraid to lose to other nations, so it started to expand its control over sea, which was in Manchuria, in China.
I think it is just the race in having empire