What led the U.S. to possess its own empire in the late 19th century?This has to do with imperialism in the U.S.

Why the U.S. Conquered an Empire:

I think the two answers already given are good ones, except that one point is stated backwards.  The desire for empire was the reason for the development of more military and naval power, not the other way around.

The big businesses desired captive markets, and closely controllable sources of resources such as bananas from Central America, a captive market in the U.S. sphere of China, cheap labor from the southern states of the U.S., and more.  Some places were captured primarily for their usefulness as naval bases to defend the empire, Midway being one such.  Hawaii had strategic location, a great harbor, pineapples, and plenty of American businessmen and pineapple planters already living there.

The idea of the white man's burden was easy to believe, since expansion of empire to facilitate it would reap economic profits.  I wonder if the American empire was ever expanded into areas where no economic profit was to be made, just to bring civilization to the natives. (?)