What motivated the U.S. to try to get its own empire in the late 19th century?

One reason for the United States' expansion in America
during the early 19th century was the idea of manifest
destiny, the belief that the U. S. was destined to extend its borders
from the Atlantic Ocean westward to the Pacific. This belief grew in part because of the
U. S.'s strong stance toward furthering democracy throughout the Americas and partly
because adding more territory would prove profitable in the long
run.

Another reason for expanding the U. S.'s empire was to
protect itself from foreign attack. Although the U. S. has been one of the world's
superpowers for nearly a century, it was not so in the 19th century. After gaining its
independence from England, the U. S. had to fight a second war with Great Britain (the
War of 1812) and a war with Mexico in order to secure its borders. Even Spain was forced
to engage the U. S. during the Spanish-American War in 1898. This war helped the U. S.
add valued territories outside the continent, including Cuba, Puerto Rico, Guam and The
Phillipines--strategic ports in the Caribbean and Pacific that would allow the nation a
more expansive world view.