Answer: John Quincy Adams used the term "Manifest Destiny" to justify the expansion of America towards the west.
Explanation: John Quincy Adams was appointed as Secretary of State by James Munroe, the U.S President in 1817. As Secretary of State he was held the responsibility on the ongoing border disputes in different areas of North America between the United States, England, Spain, and Russia. He acknowledged the American need for a robust foreign policy that encouraged the growing of dynamic capitalist orientation of the country.
So, he was the one to use the term Manifest Destiny in order to justify America's expansion. The term is widely used for territorial expansion of U.S from 1815 to 1860. During his term he acquired Florida from Spain and set the western border by Louisiana purchase. In 1843, he changed his mind and repudiated "expansionism" instead of Manifest Destiny.
Originally the term "Manifest Destiny" is generally credited to a newspaper editor John O' Sullivan in 1845.
