[63] Apart from the Monroe doctrine, his last four years as Secretary of State were less successful because he was preoccupied with his presidential campaign and refused to make compromises with other countries that might have weakened his candidacy; the result was a small-scale trade war but a successful election to the White House.
Taking office in the aftermath of the War of 1812, Adams thought that the country had been fortunate in avoiding territorial losses, and he prioritized avoiding another war with a European power, particularly Britain.[64] He also sought to avoid exacerbating sectional tensions, which had been a major issue for the country during the War of 1812.[65][c] One of the major challenges confronting Adams was how to respond to the power vacuum in Latin America that arose from Spain's weakness following the Peninsular War.[67] In addition to his foreign policy role, Adams held several domestic duties, including overseeing the 1820 Census and writing an extensive report on weights and measures.[68] The weights and measures report, a particular passion of Adams', provided an extensive historical perspective on the topic and advocated for adoption of the metric system.