Despite the ramshackle nature of the foreign affairs establishment, the Department of State was still able to make significant contributions to the nation during this period.
Of equal importance were successful negotiations that furthered American domination of the continent. The Treaty of Guadalupe Hidalgo (1848) was of key importance because it ended the Mexican War and annexed a tremendous amount of territory north and west of the Rio Grande to California. The purchase of Alaska from Russia in 1867 was also a significant triumph for diplomacy. Despite the generally amateurish nature of diplomacy at this time, no serious setbacks marred the nation's foreign affairs between 1823 and 1867.